SNASM68K 68000 Cross Assembler System Manual

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9', CROSS

PRODUCTS

LI iI ITE D

SNASM6SK

8/8/91

CopyrlEht cro$ Products Ltd 1989-91

CROSS PAOOUCIS UMI1ED

LEE06

lBMo is a regisLcd lEd.malJ( ol lnl.mni.n.l Susii.s! M-hin.s Clrp..alion.

MS DOSo b a Ggisr.Gd rEd.ma* oI Mimdr c.DoEtio..

Bi6l is a lrad€ma* ol UideM.E lnc.

Introduction

Th€ Cross Products 68000 cross assembler syslem is a high performance

68000 assembly language development syslem runninq on MS-DOS and

PC-DOS computels.

Component! ol the Svstem

Assembler

SNASM6SK converls progEms winen in 68000 assembly language inlo

€ilh€r absolute code which can be senl dir€ctly to the larget machine, CPE

(Cross Producls Executabl€) files or object moctules suilabte Jor tinking.

Debugger

SNBUO6SK allows 68000 programs running on the larg€t machine io be

remotely debugged from lh€ dgvelopment Pc. lt has acc€ss to the symbots

used in lhe source cod€ allowing lull symbolic debugging.

Llnkar

SNLINK combines objecl modules created by SNASM68X, evatuales any

erpressions which could noi b€ resolved ea ier lt can gererais output i4 a

large vaisly ol formais including direct transmission down ihe SCS| tink.

Llbrarlan

An object module library is a coll€crion ol objecl modules thai reside in one

file. SNLIB is a ulility program ihai builds and marniarns objeci modute

libraries ior fte linker.

Hardwars Link

To speed program development, lhe development PC is connecled to the

larget machine using a SCSI (smallcompuler sysiems jnlerfacei bus. The

assembler, linkerand debugger use this inlerlac€ lo send code to the targel

machine_

Environment

A program can be assemblsd and debugged without exiting lhe Biel editor

wnich grearly speeds lhe EdivAssenbte/D€bug cycte.

wavs ol u3lng SNASiI

SNASM is an extremely ilexible sysiem ihai can be used in many dittereni

ways. A few ol these approachss are giv€n here lo give an overview of the

product.

Absolde 6ds wirhod sections- no linkind

The code is be ass€mbl€d al an absolule address, specilied wilh one or

more OFG directiv€s, and then eitherserf dkectty to thsiarget machine,

placed inlo a CPE lile oroutput in pure binary fomat.

Abelute 6de with..ctions n6 tinking

The ORG address of lh€ program musl be specitied belore any seclions are

opeisd. lf groups arc not used BSS type sectio4s a€ not av'aitabt€, and

sedions areplacsd in memory in the oder they occur. I groups ar€ used.

lh€y define lhe ordedng ot seclions in memory, and a ow-BSS type and

absolule word addressable sections

Lillirq

Each source fil€ is assembted usinq lhe /L switci io oroduce an obiect

module. Source modul€s cannot contain ORG directives. Th€ modites are

linksd to produce any, ot ths output types supported by ttre assemUei pruJ

some machine specilic relocatabte tomats.

There is no ne€d to use sectiors orgroups when Droduci.q tinkabte outout

Dtn many more tunciions ars avaitabb it ihey are ised. -

Hardwere R.dutremants

SNASMoSK requirss ihe tottowing minimum contigurarion :

, IBM-PC or compaiibte compuier

. One lree I or 16 bi! stor

- 256K ol memoru

. MS.DOS 2.0 oilater

. A hard disk

we strongly recominend :.

. 8MH2 IBM PC/AT or taster

. A fai haKl disk

. 640K ol main memory and a l tvtb RAM disk

. OOS 3.0 or above

Hardware lnstallation

conligurho th. PC card

The card can reside at one ot several addresses in the PC's pon map. The

links labelled 0-7 are used to sel the address as lollows :'

Address

300-307

308-30F

310-317

318,31F

380,387

388,38F

390-397

7 3S8-39F

The cad js supplied wilh llnk 6 connecled so it is al address 390 hex.

The SCSI bus suppo(s up to eight devices, each ol which musl have a

ditferonl SCSI device number.

The links labell€d Al ar€ used to s6t th€ ScSldevice numberofth€ cad

andlhe DMA and lntemJpi channels the card willuse.

ult

t-rt

t__l!

01234567

IITTIM

IITTTTTTII

l]!t

lnlerrupis are not cLrnonlly us€d so links A and Bshould be lefi

unconnsctsd. The cad ls supplied wilh linl6 C and D connecied so the card

uses DMA chann€l I . l, you wanl to us6 DMA channel 3 move both jumpers

to E end F, or il you don't wanl to use hardware DMA at all remove both

linl(s.

The cad is supplied wilh links G and H .onnscl€d giving the card a SCSI

device number of 6. This will only n€ed cnanging il it clashss wi another

dsvics on lhe SCSI bus.

Fltilno lhe Card

1) Vedly lhal no power is being supplied lo the compuler

2i Rsrnov€ the compute/s case,

3) Check thal lhe address and DMA senings olihe card will nol cause it

to clash wilh any olher cards in lhe computer.

4) Local€ afi smply slol and rsmove the backplate cover,

5) lnslallthe SCS|card by lirmly butcareiully prcssing lt down into ihe

slol.

6) Sscllr€ the card wilh lhe screw you removed from lhs

backplale.

7) Replece the compute/s case.

ll you changed the seilings oi lhe card make surc you know lhe addr€ss and

DMA channel you selected es you witl need this inlomation to comptete

insrallation.

Funcion

tFo5

tBoT

DROl

DACKl

DRO3

DACK3

Bii 2

Bil 1

Bir 0SCSI lD of card

Software lnstallatlon

Itlote: The SNASM inslall program is d€sign€d 10 customiss lhe Briel texl

ediio/s envircnm€ntlo €nable SNASM to wofi lrcm $ilhin Aiel. ll you

int€nd to work in lhis manner you should install Bie, before you inslall

SNASM,

Th€ install proghm provid€d on your SNASM disl bution disk will

automatically inslall the whole SNASM system . (Allquefies rrom lhe

program asking lorossr inpul ar€ t€minated '[y/nr. Hitting the ESoAPE k€y

at rhis prompr willabod immedialely.)

lnslall will ask ior the lollowing inlomalion:

1, lnslall ,irst ch€cl,s to see il il can fnd lhe defaull direclory lo copy lhe

SNASM executable liles io. This is o:\SNASM. lnstallwillgive the userthe

oplion to speci, any olher djr€clory.

2, The inslall program will now ask Jor th€ syst€m bool driv€ and check that it

can rincl an asloexec.bat lile there. ll willpersist in asking ior this in,ormalion

unlil it can find an auloexec-bal file-

3. Next it r€quir€slhe name olthe disk drivs in which the SNASM

distdbution disk is reslding.

,1. The lnstallprcgram will now ask ilthe user requires 10 backlp old riles. lf

lhe answer is yes any fles in the targel direclory ollhe

on€ aboul lo be coplsd onlo it willbe saved (in thal dircctory)wilh lheir lile

€xtension changed lo'.old'. This oplion takes eflectlhroughoul lhe install

process and il il is not selecled lhe copy proc€ss willstop lor every iile lo ask

"lilename exists Ov€Iwrile/Backup/overwiie AlliO/B/Al'

lhese oplions have the lollowing eflects:

O: overwrite this lile repeat query ior nexl lile.

B:save old lile wilh '.old' extension rcpeat query.

A:oveMnte allliles ol same nameswithoui asking

(hroughoullhe whole of rhe lnsrallprccess).

5. Should lnslall delect lhal th€ dkectory holding rhe executable liles is nol

on the search peth ollhe use,s machin€ it will ask il il should add ii.

6.lnsilatlwill nexl looktorthe BPATH and BHELP environmental vaiables lo

delermifle wherc to copy the Biel mados and menu files lo. li willdisplay a

message asking ilthis isdssi€ble: as Bdei expects to lind lhem inthis

localion it is aclvisable 10 do so.

7. Berore ediling the auloexec.bal ile, lnslall will ask lhe useril a backup

should bs created(as autoexec.old). li willthen proceed lo sel several llags

within lhs Bri€f environmenlal variables and add ihe clmmand to install ihe

SCSILINK software on boolup. lnslall will always ask belore editing any

portion ol lho autoexec.bat lile.

8, ll lnsiall lsaves a message on exil saying lhat ihe otd SNAST!,| macro stad-

up code is presenl in lle us€rs slartup.cb macro lile lhis is due to a changs

in the manner in which lh6 SNASM Bdel macros ar6 initiated on starring an

ediling session. Th€ llne 1oad_macro('snasm")' should bs remov€d {rom the

fi16 startup.cb (r€siding in the direclory pointed lo by the BPATH

envircnmenlal variabls - \bieflmacros by d€rauh ) andihe lite re-compil€d,

Ths communicaiions belrxeen the PC and the target machine are handted

by a program called SCSILINK which mu$ be instatted botore any orth€

other programs can be run. lnstallwilladd a tinelo do thjsyour

auloexec-bal llls, The inrormation belowwillb€ ot us€ i, you wish to instattit

at a nondelault addrcss.

UsaE€:SCSILINK addr€ssl,D1[,]?]

lhe delault is

SCSILINK 390,D1

Th€ address is whalever was s€l using links 0-7 on the SNASM PC card

and lhe number alt€r the D should be rhe DMA chann€lyou are using.

ll no DMAchaflnelis specilied hardware DMA wilt nol be used and unless

you have a fasl compul€rdata lransmission spesd wjllbe reduced.

The lparameleris usedlo giv€ the card a diflerent SCS|dsvice number

wilhoul opening th€ compuler and changing lhe linls, howeverthis is nol

SCS|L|NKchecks for th€ exisience ol lhe PC cad as it instatts irsett. and

repons any erors at lhis lime.

g.You should r€-s€t your computer when lnstallllnishes io benefil from lh€

new SNASM environment.

Running the Assembler

ll you inlend uslng SNASMoSK as a sland alone assembler instead o,

tunning itlrom within BBIEF you must be familiarwith lhe command lin€

Command lln. Svnt r

SNASM68k /switches sourceiile,objectfi le,symbollile,lisllile,t€mpf ile

Swllchas /b number Set si2e of inlernal bulf€rs (Kbytes 2-64)

enable lisling of lines lhal are in lailed

condilional struciures

/d Debug mode - do no! run

/6 symb=value Equale symbollo value

/g Wdte non{lobal symbols to linker objecl

tit€

Display inlormation window dudng

assembly

4 path specily include lile search palh

/k Allow uss of il€q sic,

,l produc€ linkable oulpul iile

/m B(pand macros in lislings

/o opls Set assembl€r options/optimisations

,! Produce pur€ binary insl€ad ot.CPE

,v wile equales lo symbol/linker ,ile

,2 include tin€ number inro. in linkerlile

Se€ the section on Options lalerin this manuallora iulllist olthe assembler

options and oplimisalions-

Sourcetlle File containing 68000 sourc€ to bs assembted_ tf this is

omitl€d SNASM6SK willpdni rhe above inlonnation in a help

message.ll no exlension is givsn Jorlhe source lile it is

assumed lo be ,68K.

Oblectflto Flle lo reclive objecl cod€ ouiput. lllhls is omitted no object

code will be generaled. ll you want the object code lo be s€fi

lo a largel computer use T?: as lhe objec ile wh€re ? is the

SCSId€vic€ number ol the laEol.

Symbolllle File to rcc€ive symbollable inrormalion iordebugger.

Llsttllo Fil6 to receive any lisling oulpul.

Temptlle File 1o be used lor any data lhat will not lit in memorywhitst

assembling. lllhis is omitled the lile willbe called

SNASM.TMP ora unique nam€ il your DOS veEion is high

enough.

e.g-

SNASM68K /o ow+,an+,e+ t€sl,68k,17:,|€si.sym,,e:

Assembles lesl.68k wilh warnings reporled, allernate numerics enabled and

eror line printing suppressed. Obj€cl cod€ will be sent lo the targel with

SCSI device number 7. No lisling will be generated, symbols wiil be writien

to lesl.sym and the temporary rile will be gsnsraled on disk E:.

Each tim€ SNASMGSK is run it check for an optional €nvironment vaiable

called SNASM6SK which contains delaull swilchss, oplions and filespecs.

eg-

s€l snasm6Sk=/c-,17:,,,e:\tmp

Disables case s6nsilivily, makes delault output go to larget 7 and sets lhe

dolaull lemporary lile 1o be €ltmp. Anylhing set in the environmenl variable

can be over-iddon on lhe command lins,

Assembly can be slopp€d by pressing Controlc, or il you are ass€mbling

lrom within Bdeland you arc using the inlomation window, by pressing Esc.

l, the rilsl it€m on the cofimend line starts wilh an at sign (@) it is taken to be

ihe name ol a fil€ conlaining lhe assemblsr options,

eg-

SNASMS8K @snasm.cmd

wh€re snasm.cnd contains :.

test.68k,

t7t,

iest-tst

SNASM6SK /j cl\include /e z=1 tes1.68k,t7:,,t€sl.lst

Bunnlnd lrom wirhln BriEI

1. Th€ Brie, edilor macrcs thal interlace SNASM to lh€ editor have b€en

revised to aork wjth lh6 Crcss Producls make utilily SnMake and h€ncs

provide a beller working environmont lorlhe SNASM user. ln praclical tems

ihis m€ans that wjthin Bde, the dialogu6-box interface to SNASM has been

complolely sc6pped and now relies on using SnMakE and ils associaied

'project liles'lortho selting up and ex€culing of exlernal commands. Whilsl

Ihis involves slightly morc wo in iriiial setling-up il oflers longertern iiF€

sevings and much more llexibilily,

Using SnMake is delalled ln lhe sed,on 'Using SnMake' and will not be

gon€ inio in greai delail here. Th€ SNASM €nvironment now relies on the

creation ol a'projed file'foreach prcjscl the user is undenaking. Thes€ ar€

tiles dilised by SnMake whlch hold inlorfiation aboul ihe tite dependencios

lor lhat projecl and the rules by which the output lile(s) can be crcaled

according to those dep€ndencies. (5o6 Using SnMake' ). This means that

commancls and thear optjons arg put into the p,oject lfle as they would be

enl€r€d lrom the cofimand lin€, instead ot being set up in the dialogue-box

The Snasm main m€nu ls lnvok€d by pressing All-Fg. The menu optionsthat

ale available are discuss€d in sequence below. Navigation lhrough lhe

rnenus is dooe using lh€ up and clown arrow ksys, ssleci items using the

rsluh key, escaD€ willexil allmenus.

liake. Keyboard€quivalentAlt-Flo-

Thls opllon invokes SnMake on the cufienlly select€d proj€cl ril€.

S6l6ci Prol.ct File. Keyboard equivalent Cli-Fg.

When lhis is seleclad il brings up awindow showing allth€ lil€s

wilh a '.prj' €xt€nsion in th€ cunenl direciory, il one is cuirently

s€lecled il wil be highlighled. These are rho poject flss. The

fiIst llne olthe projecl ril€s is displayed in lhis window as an

aid tolhe users memory il multiple proiect lilss are presenl in

lh€ currenl direclory, See lhe sub.m€nu item 'Show comm€nt

lines'lor more informalion on putting such comments inlo prcject

files. Sel€cling ong of lhes6 libnames willb ng up a sub-menu

otfering lour options.

1. S€l6ct this file. Selecting this optlon make ths highlighted

project lile 'cuffenl', l.e- invold g th€ mak€ option will stari

snMak€ wiih th€ highlighted proj€ct lil€.

2. Select .nd Make. Mak6 th€ Hghlighled projeci lile cLrffent and

invoksthe make utility at lhe sam€ tim€.

3. Show comment lln6s, This displays allthe texr in the project

file from lh€ top ollhe lile to the [SnMake] tabet. This is a

rcquired label in a projoct fil€ and SnMake does not begin to gars€

lh€ fl6 rorinpul unlilit encounlers this label. Thus any t€xt

can be placed belor€ this labsl withou! causing an enor.

.1. Edn thts flte. Edit lhe hightighied project tite.

Nole: only sub"msnu options 1 and 2 alerlh6 setting ollhe

cur€nl proiect lile.

O.bug. KeyboardequivalentCti-Flo.

This option €nt€lslhe debugger sp€dfied in th€ curent project

lile.(See'Using SnMake'for more iniomation on sening the

debugger).

Set Dsbug Hode. No keyboad squivalenl.

Selecting this oplion brings up a sub-menu with onty two options:

On and Ofl, one ol which will bs hignlighted. These oplions

controllhe setling ollhe special macro '$l' in the proiecl lile.

This macro €xpands 10 lhe setlings ol lhe debug and inio swirches

on lhe Snasm command tine. lnio mode is always on when SnMake

is invoked korn within Bi€f, making Snasm and Snlink bring up

slatLrs windows allowing the user 10 monilor their progress.

Debug mode can be sel lrom this menu oplion, determining

whelherths progam being Inade, (assuming il is being

downloaded lo a target machhe) is run immedialely (debug mode

Oil) or waiis wiih lhe program counter s€l to th€ valu6 sp€cifi€d

by lhe user with the 'regs dircclive (d€bug mod€ - On). ll must be

slress€d that thjs conlrol only slsms lrom lhe corect use ot lhe

special macro $l'in the ploiect iile. (See'Using SnMake).

Eveluete. Keyboard equivalenlCtd-E.

This option invok€s lhe expression evaluaror sp€cilied ln the

curent project lile.(See'using SnMake'lor more inlormalion on

s€tting lhe expr€ssion evalualor), ll any t€rl jn the curentwindow is

highlightedlhis tunction willanefipl to pass it to the

expression evalualor, if not it will prcmpl ,or inpui on the Biel

status line.

Jump to label. Koyboard equivalent Cid-G.

This oplion examines the currenl cursor poslllon and d€lemines

it it is on a valid label(SNASM 68000 assembly language syntar).

llso itjump6 to lhal label, iJ nol il pmmpls lor a labelname to

Undo lasl labet. Keyboard equivalent Cl F.

This oplion undoes the offscrs ol 'Jump ro label'.

Sav€ all bull6rs. Keyboard equival€nt All-S.

This option saves all butlers orrrenlly being edil6d.

Errot wlndou. K€yboard equivalent Cld-Q.

This option opens an error window lo display the cunent conlenls

ollhe eror ,ile 'erlors.eri in the cLrrrent directory. This is

lhe file to which allenoroulpd is r€direcled by Snlvaks. llth6re

are enoE in a ional that lhis lunclion can undersland(i.e.

similarlo Snasm and Snli.k)lhe user can sl6p lhrough lhe errors

using th€ up and down anow keys. Hitting enter on a highlighled

enorwilltakethe us€r to the reponed erorposition in ths r€levard

sourcs fle. The 'Home' and 'End' keys can beused lo move lrom lhe

top and botlom oi lhe eror tutfer rcspectiv€ly and pressing Cld whilsl

using the up and down arow kels allowsthe userto mov€ around in

th€ eror bufter line by line. Slriking ent€ron a lin€ that tie macros

do noi recognis€ as coniaining an enor msssage witl result in an

eror message lo thal ellect.

K€yboard equivalent Ctd'N-

This option scans the lil€ 'errors.en' and moves the culsorlo the

nert gnor in lhg sorirce code. Bepealed invocations willstep

through lhe €Irors, On linding no mors errors the iunclion will

display a message lo lhal eflect on lhe slatus lins,

SCSI errors lxhllit assemblino

l, you ale s€nding lhe object oulpul down the SCSI harclwarc you may

occasionally see an error messao€ end be given lhe option to Abon, Retry or

Bus Bos€l ald R€try. The fiessage willlellyou wher6 the enor was detecleo

(Locally or by lhe Targel)and whal causedthe eror.

Examplas

LOCAL: Target nol available

LOCAL: Bus nol ava aue

ll lh€ errcr was csus€d by a power spik€ or by ih€ targei being tempora ly

unavailabl€ Retry will usually qet lhinEs Eoino aoain. l, ihis does not work

Bus Beset and Retry may b€ ellecliv€ as it resets alt devices on lh€ SCSI

bus and r€conn€cts wilh the 1ar9e1 belore having another go, Abolt should

be used il neilherofth€ abovs wo*, or illhe eror was caus€d by something

likelhe targel running outol memory, es this caus€s lhs ass€mblerto stop

assembling and €xil.

Debugglng

SNBUG6SK ls a lulHeatured debuggerwhich uses the SCSI hardwar€ to

enable you to r€motely d€bug a program running on your target machine.

Th€ dsbugger has eccess lo symbols within your program and its

expression €valuator has all th€ t€alurcs ol SNASM6SK which allows lull

symbolic d€bugging.

Th€ SNAUGoSK debugg€r lels you :-

. Trace your code Inslruclion by instruclion

, Sse lh€ varues ol your variables rn a van€ty ol lormais

. Change ihe value ol6ny vaiabl€ or msmory locaiion

. Set breakpoinls lo slop when an instruction is exeMed or wh€n

a cendn condilion is mel.

To make it easier to mov€ between Bdel lor €daling and SNBUG6SK ror

d€bugging, where possible we hav€ lri€d lo use Briefs conlrot keys and

The Lht Soflwar.

The Unk Sottware usually resides in ROM on lh6 target machine inlerface

and it communicales wilh lhe ass€mbler and debugger. To snable the target

machine lo b€ d€bugg€d lhe unk sonware uses sevsralol the target

machines vectorc. These are :

Veclor Number AddBs Flnction

2 0008

3 000c

4 0010

5 0014

6 0018

7 001c

I 0020

I 0024

32 0080

lllegal inslruction

Zero divide

Chk inslruclion

Pivilege violation

Trace

Trap0

The debuggercan Oain control o, th6 laEel whenever ons or lhe above

exceplions occurs. ll your program is running noftnally none ol ihe above

should happen, so io ensure thd lhs debugger can gain conlrol 'l rt requires

you should execute a lrapo inslruction al rcgulerinleruals. This can, ilyou

wanl, b€ wilhin an inlerrupt rouline such as vedical ,lyback.

Command llne Syniar

SNBUG63K /swilches syrnbolf ile

The s$1lches can be anerlhe symbol lile name il you ldish, and you are atso

allowed lo sp€cily seve€t symbol liles,

Switches Load conliguralion lile

Thjs is to allow expressions to be

evaluated irom within 8d€f, you will no1

Load CPE nle inlo target

Ovedd€ video bios dala screen rows

Turn continuous updale on or ofl

Sp€cify rale ol update (See All-l)

Set lab€l l€vel

Set largel lD

Use Hercules graphics ddvers

Hali target al debugger stariup

Example

snbug6Sk /m128 main.sym diskulil.sym

GenErrl Concepts

The dsbuggeis display consisis ol a number o, wjndows ol live basic lypes.

These are Begisler, Disassembly, Memory,Walch and File. Wndows can be

splitto lom lwo windows, th€ boderbetween two wjndows can b€ moved or

rsmoved and the lype ol wlndows can be changed.

You can have as many D,sasssmbly, Memory, Watch and lil€ windows as

you want bui you are resiicied lo only one regisierwinsow. You can move

belween windows al will, wlth lhe curenrly aclive window b€ing highlignied.

Wilhin each window lhe keyboad controls allowe you io change tie

windowb slate orsend qlmmandslo thetaEet machine.

ll conlinuous updale mode is on,lhs windows are reiresh€d at whatever rate

is s€l,orlhe update interval. lllhis mode is not €nabl€d windows are onty

updaled when soms thing happens, i.€. a key is prsssed or a breakpoinl

The r€glst€r window displays lhe contents o, all o, the processo/s qeneral

registers. ahe cuisor can be moved around lh€ window and lhe contenls ol

any olthe regisleB changsd €ilher by typing the newvalue dkectly or by

pressing R€tum and €nledng an expression.

Dlsassembly wlndow

Thjs wiidow displays your code in disassembled ,ormat. Wh€r€ possible

symbols are used inslead of hex addresses lo make the 'codei more

r€adable. lfthe largets PC is al one ofthe lines in lh€ disassembty ir is

marked wirh a gr€al€rlhan sign (>). lfa breakpoint is sel lhe colour oithe

/lNumber

lNumbsr

/Number

/tNumbor

/gNumb€r

lin€ changes and th6 brcakpoinl expression and courl arc displayed afler

ll ihe debugger has b€en lold the name ol lhe symbot iable n reptaces

numefic values wlh lheir symbolic equivalents. Exaclly whgrc this ,s done ls

conlrorled using lhe label level. Local labels will oe seen ,n lh6 disassemb,y

window if lhey have been enabled at assemblylime using the v+/- option.

L6v€l

Memory is displayed In h6x lormal as eilhsr byles, words or tong words. As

in lhe Begist€r wndow you c6n dir€clly enier new data or pr6ss reium io

erder an expression.

Th€ Waich window is usedto display thecont€nis ot memory at an address

given by an erpression which can, ol courss. conrain symbols lt rs used to

monilorlh€ value ol variables and lables as your program runs.

This window rs used io view laxt lilss. l,suatty sorrrc€ code. You can browse

around lhe iile and clo simple searches, bLt you cannot make changss lo lhe

lile-

Conlldur.ilon Flle!

when lhe debugger slans up ii geis ils inilrat siaie trom a contiguration t.te

called someth.ng like .SNBUG68K.CF? where ? s tne SCS| tD ot your

chosen larg€|. The /s switch can be used on lhe command line io aause a

diflerent coniig fil€ to be loaded. These titss can be saved and loaded al

anylime during lhe debugging session, so you can have a tew of your mosi

usetul conliguralions s€v€d on disk. ll a contiguEjion tite retels td a symbot

which no longer exists then thal pan ot lhe coitiguralion witt be Onoreit. tf a

conliguralion lile was saved wilh the debuqqer in a video fiode ivih a

r€solu{on ditterenl to lhe curr€nt one. you witt b€ given ihe choice ot either

swilching inlo lhe nsw mode. orignodng ihe fte a[ogelh€r

Ihe only enties in the contrg tite that you wrt, usualy need lo chalge are

lhose which specily lhs areas ol lh€ targets memory lhal can be rcrd and

wntl6n. This intormalron ls ussd lo prev€ ths debugger lrying lo access

memory areas which would calse an address error;itthe link io the target

goes down when you look al cedai. memory areas or it sohe arcas appea,

lo coniajn zeros ihen lhese sniriss reed to be changed.

You can €dil lh€ conrig lile, using a ten ediiorsuch as Bri6f, and chang€ the

memory areas und€rlh€ headings #readram and i'wdleram, the formi is a

Ellecl

No symbols excepl ln addr€ss ,ield

As abov€ plus non-immedale or oflset symbols

All the abovs plus long immediat€

Allhe above plus oftsel(An)

All the ebove plus ofis€t(An,Dn)

simple lisl ol start and end addrcsses ot vatid areas, and you can have as

f€w or as ma4y entnes as you wish. Pt€as€ ke€p lhe fofliat ot ihe config tite

id€nlicsl lo lh6 odginal esbihelwise ths debugder can hav€ p.obtems -

r€ading il.

Prombt Hlstorv

whenever lhe debugger prompls lor a reply such as an expression or a

b'sakpoi condilion, you ci! nep back through otd rcptiea to that prompl

using cursor up and down. Tie prompt line can be edled with culsor tefl and

right, wilh homs, end and back"space perloming as you would erp€ct,

Svmbol Compl.tl6n

whsn€veryou are entering an €xprcssion you c{ln get lhe debuggerto try lo

compl€t€ lhe name olthe symbolyou arc ryping using Atr-N. t hAre arc

s6v€ral symbols which start with th€ text you heve enl€red, lhen you can

cycl€ lhEugh thes€ by pressinq AI-N aoain,

Erpr.s.lon Evaluator

The debuggeruseslhe same expression €valualor as the assembterwith

the lollowing chaog€s :-

. Ths d€laull base is H€xadecimal. Decimal numbers are prec€ded by a

hash (f)

. Processor regislers can be used In sxoressions

. Square bracksts around an €xpression are used to pertom indiroction.

The dobugger felches a byl€. word or long word lmdr the targ6t, end sign

€xtends ir be{or€ using it in the expr€ssioi. Long wods are tatched by

debull wilh the @ operalor berng used to chanaethis as shown b€toiv.

Examples

100 100 h€x, 256 dedmal

#100 100 decimal

Iaol Long word at AO

Ia0+d0.wl@w+ai F€tch the wod trom a0+d0, sign €xtend ii and add il lo

Tte.b, .w and,loperaioE which sign extend lhsiroperators trom the

specili€d l€ngth io a long woE can ctash wilh dots in tabet names. I this

occurs you can eilher bracket lhe expression and pul th€ .w oulside the

brackets or use \w inst€ad just as in the assembler.

Kevboard Controlc

General (nolk in all windows)

F1 Move to adjacent window

F2 tbve a window edoe

Fg Splil a window -

F4 R€mov€ a window edge

Cttlz

shifl-F1

cl+F2

AII.L

cr -L

AII.H

AII.D

Att x

ctd-x

llt-z

AII.S

cld-R

Esc

Shilt-Esc

Ah.U

AtH

Ctrl-F

F10

shifl-F10

Att-0..7

[,love lo adjacenl window (Tlese may not wofi on all

keyboards)

I\rove cu Isor lo lhe top ol lhs window. ln the Regisl€r and

Watch windows only lhe cursor moves whereas in lh6

Disassembly and M€mory windows the window address is

changsd so lhat the iiem underlhe cutsor moves io the $an

Toggle Fullscreen display on curent window

Chang€ window type

Reslar! debugging s€ssion (when using a CPE fil€)

Sel window lock sxpression and lum on lock.

Toggle window locl on/ofl. (Prompis lorerpression it one

hasn'l been enlered)

Display creation dal€ ol debugger

Exitdebugger (Automalically saves cunent slate lo

SNBUG6SK.CF?)

Eril wilhoul saving stale

DOS gateway Type exir', lo relurn io debugger

save laEel regisleB

Resiors saved regisleF

Resel. SSP and PC are loaded lom locations O and 4, SR is

load€d wilh S2700.

Hall targ€t machine as soon as possibte

Haltlarget inachine and tum ot irngrrupis,DMA

Toggle conlinual updale mod€ on/ofl. lDelault ott)

Sei inlerual for conlinual updare il l8tis o{ a sec6rd. {o=Ftal

out, 2=9 limes p€r second, l8=once p6r second)

Upload bytes lrom targst into e lite

Download by.les lrcm a fle to tarEst memory

Save cufl€nt conl]guraiion to a lile

Load conliguralion il€

Change targel number. The currenl setup is saved lo lh€

conlig lile and a new conlig lite torlhe new targel is toaded.

Eeglsier window

Arrou6 irove qJrsor

Reium Change reoislels valu€ lo resull of an expression

0-9/A-F Enler new valu€s at cursor

llemory wlndow

Arrows Mova cursor

Relum

0-9/A-F

AIt.G

Move cursor up/down a page al a lime

Chango msmory valu€ lo r€sult otan oxprsssion

Enler new values at cursor

Goto €xprsssion, Changes window slarl address lo result ol

Swilch bstwe€n byl€, l]vord and long word display

Set window slarl to value ol long l|ord under cursor

lncr€m€nUdecrcment value under culsor

lns Add e new walch expression

Del Remove a watch expression

Dlsass€mbly window

up/down Llne up/down

leflnght irove a word al a time

ilov€ curcor up/down a page al a lim€

Alt-G Golo gxpression, Moves cuEorto r€sult ol expr€ssion

Tab Move drsorlo PC

Shift'Tab Move PC to cursor

Alt-C Attach condilion lo brealeoinl at cursor

Cld.C Attach counl lo breakpoint d srrsor

Alt-Fs B€set all breakpoint counts

F5 Toggle breakpoint al cursor

F6 Run cld€ at larg€t unli! instruclion al cursor

F7 Trac€s. Steps ov€rtraps and line NF

F8 St€p ov€r. St€ps ovsrsubroutine calls and dblas

Fg Starl laEet executing cod€ lrom oJrent PC

shift-F5

shin-F5

shitt-F7

shift.F9

Clear all breakpoinls

Res€t all breakpoint counts

Forced trace. Traces down lraps and lin€ A/F

Run lo sp€cii€d addr€ss

lncremenvdscrem€nt label level

'17

File Window

up/down Line up/down

l€turight Characl€rlelvrighl

irove cursor up/down a page at a lim6

Home/End Beginning/End ol file

Enter Change lile nam6

Alr'G Goto lin6

All-S Search

Alt-N Next ocdrrance ol search slring

tlerctrEr-IxEsr

This swilch, wlich should only b€ used wilh heroJles mono cards, causos

lhe debuggerto us€ its buit-in hi'rssolution hercules diveElo give you

many more rows ol characl€B on ths scr€€n, The /90 uses 80x50 mode and

/gl 90r4ai.

Source Code Syntax

The slalemsnls in 68000 source code arc eithor instructions which can be

translaled into 68000 machine cods, or dir€ctives. Di.eclives are ussd lo

controllhe operation ofths ass€mblerand how it lnteDrcts the source c!de.

SNASM6SK supports the Motorola standard 68000 mnemonics. Thes€

mnemonics are not sxF,lained in this manual as il is nol inlended to be a

58000luiorial.

Stalemenl Format

Slal€menls have the tollowing general form r

op€ralion operand commenl

label

Ndes

. Lab€ls always stad inlh6lirsl column unless they €nd with acoton (:).

. Fisrds are separaied by tabs orspaces.

. Anyihing on a line anerlhe op€ration and operand ls taken as a comment but

lo avoid conlusion il is r€commended thal lhey bsgrn wiih a semi-coton.'

. Blank lines and lines coniaining only tab6 and spaces are comments

. Lines slarling wilh a semi-c{lon or an ast€nskare commenls.

. Lines staning wilh an equals sign are case statement setectors,

Labels end Svhbols

kbels.nd Symbols nust ob€y lhe lollowing rures

. A symbol contains characlers from the set:

A-Z

0-9

Unde6corc L) and Oot (.) disils

. Digits may not be lhe lllsl charactsr of a symbol except in loca, labels.

. A symbol may optionally be lollowed by acolon when il is detined but nol

when it is r€l€r€nced

. Local labels bsgin wiih an al (@) or optionatty a dol(.) Tlese are e,(ptained

later in ihls manual.

As labelscan cont6in dots it ls possibte tor there sometinres to be con,usion

aboui whelher adol is pan ol e labelor a siz6 moditier.ltthis happens you

1 The wS oplion makes rhe dsemuer lnslst on a seri-@ton betore comenls. see the

ssclion on oplDns ior moro inronEton.

can €jlh6r bracket the expression oruse backslash 0)in place ot the dot on

lhe size modilier.

Last_One

Erempl€s ol symbots

Mysymbol A A135

@Local @2

The assembler has various predelined constanls available which usuatly

siarl wilh an undeBcoie. ll you want 10 avoid clashes wilh any luture ones ol

theselhen avoid the use ol undeGcore as the lilsl character ot a label.

lnieder constanrs

Thedelault base ror constanis is decimal unl€ss the RADIX operalor is us€d

to chang€ it. Hexad€cimal numb€Is arc pr€ceded by a dollarsign and

binaiy numbeB by a penentsign. lryou want to use theASCllvalue ol a

characler as a conslant place il in quotes. ll a character is preced€d by caret

(^) the corresponding culrolcharacter is subsl 0t6d.

CoL(.nt DecimalVelue

1234

$A0

'1234

160

'?"

BADU

Syni.x FADIX cdnstant

ljnless you tellil olh€Mise lhe assembler assu mes thai the radtr ot a

numbernol preceded by $ or% is decimal. Wiih the RADTX operaoryou can

change lhis delaull lo any valu€ betwsen 2 (binary) and t6 (heredeclmat).

The argumenl lo lhs BADIX op€raior is always evituated using decimd aa

Irh€ AN (alternale numeic) option is enabtsd, you can atso detile

conslanls in lh€ Zlogllnlel lashion. Th€ number, which must begin wiih a

decimal digil, is lollowed by H,D,Oor B to specily the base as Hdx, Decimal,

Oclalor Binary respeclively, This fsaiu.e does notwork il ihe defaul rcdix is

>1 0 as B and D ar€ valid hex digits.

Location Cou.rer

An asleisk (') wh€n us€d as a conslanl substiluteslhe value olthe cuiienl

%i01010 42

'4', 65

dc.b 'Hello Wofld

'-Mysldng

Example

MyString

MyStringLen

Exotesslons

SNASM6SK uses a signed

th€ lollowing operators :-

32-bit integel expression evalualor which has

Operators

I!Lg!

;

Comparlson

Funclions

der{)

reo

nars0

sircmp0

stden0

inslr0

lvpe0

sqn0

secl0

ofiseo

filesize0

-x

X+Y

x.Y

)sY

x%Y

x&Y

x!Y

-x

(x)

DEF(X)

REF(x)

NARG(X)

STRC P(S1,S2)

STBLEN(S1)

rNsrB([x,]s1,s2)

TYPE(X)

soRr(x)

sEcT(x)

oFFSET(X)

FtLEStZE(S1)

Speclal constants

narg NABG

_rs __R S

Jear, _monlh, _day, _weekday,

_houls, -minules, ssconds

posiiive(unary)

negalive(unary)

addition

mulliplicalion

quotient oJ divislon

remaindsr ol division

logical and

logical inclusiv€ or

logical complimenl

shi,t X lefr (Y iimes)

shifl X ight (Y limes)

grealerlhan

grealer lhan or equals

symboldelined

parameleis argumenl counl

sling compa son

stfing lengih

typ€ ol a symbol

Size ofa lile

parameleB passed to macro

currenivalue ol rc counler

lime and daie conslanls

For a lrue rosull compaison operaloB relurn -1, lorlatse lhey retum O.

Some ot ihs above lu4cliols and consiarts may be un.amitia. bur ihey are

erplained laier in ihe m€nual. '

Note

Unlike some assembleF SNASM6SK uses a lull 32-bit sxpresston

evaluator, so you must bs careful when using large numb€6. A number

needs b[ 31 sel lo be negalive, nol jun bit 23.

Erampls

Pa)o €qu $FF8240 ;posrl,ve numbe/

i lhe abovo is NOT lhe sm. aq

PalO €qu

Op.r.lol Prccedence

SNASM68K evaluales expressions using the totlowing rutes :

. Op€alors wiih higher pr€cedence are perlohed betore ones wilh tower

. gp€lalors with lh€ 6ame precedenc€ are pedorned lelt to ight

. Expr€ssions in parenihesis are always evaruated ,irsl as thei have the

high€si priodty

The table below shows opeElor precedence in dsscending ordet

+, -, - (unary)

+, - (binary)

li is usually bssl to parenthesiz€ an erpression to make ii ctear lo bolh

yoursell and lhe assembl€rwhat you msan,

ALIAS and DISABLE

llany ollh€ assemble/s pr€-defined constants orlunciions ctash with

symbols in yourprogram or il you simply donl trke th€ cuneni names yoJ

can remove the delinitions wrlh the DISABLE command. As lh s woutd make

the funciion inaccessable you can Jirsi rename ii using AL|AS.

$FFFF8240 ; negativ€ numberl

Example

-Tvpe

Typo

alias lype

tvps

0 ; Typ€ ol account

ALIAS ard DISABLE can be ussd on ary nams {symDot. turct,on macro etc)

that lhe assembler has akeady encounlered bLlr il cannoi be used lo renrove

or rename assemblsr inslructions or direciives-

Equates

Equates are a way o, attaching a symbolic name to a conslanl orvariable

numedc valug- This improves cod€ readability and means onty having to

change one line lo change lhe value orthe constant.

Perman.nl Edual€s

EOU

This islhe mosl common lyp€ ol equaie. Tle symbolon the len handside ot

lhe lin€ on which the EOU directiv€ occurs is assigned rhe resutt ofthe

€xpression on rhe dghl.

Example3

lOPort

Entries

EnlryLenglh

Tolalsize

8it3

equ

€qu

-1

$300

Enld€s'EnlryLength

Onc€ a symbolis given avalue with the EOU directive any atempt to assign

e newvalue willgenerale an error.

ll is podeclly l€galto re.equare asymbolto the same value as ir atready

holds,. These are called banign red€nnitions and will usually occlr when an

include ,ile delines hardware localions tor ilsell ihat the main prog€m also

Mosl assembl€rinsisl lhal th€ €xpression lo which the symbolis equaled

conlains no loMard r€ferences. With SNASM6SK how€ver, as much as

possible ol the exprsssion is evaluai€d, andlhe r€mainder olth€ wofi is

don€ at the end ol the lirst pass. You should be careiut when ,olwad

referencing local symbols in ihls way. as lhey wirr probabry not exist when

lhe evaluation is done

Bedelinable Equal€s

SET and =

Wh€reas EQU is used ior delining conslanls SET and = are used tor

delining variables. A symboldelined with either ollhese directives can have

its value changod as onen as you like. Th€s€ vadables arc trequentty us€d

as loop counlels and scrE ch vadablss jn macros.

Example

Freespac€ set 0

Freespac€+l 024 ; 1 K more lree her6

; zero tree space lolal

Freespaco ;;

Set and = are synonymous-

e.g.

Tolal

= Total+1

SNASM6SX generales a waming il a variable is reierenced belore it is

delined, lJ you do loMard relerence a vaiable, the value subsiiluled willbe

lh€ value ol lhe variable al lhe end ol lhe lirct pass.

Unlike EOU lhe aqument ot SET musl not conlain lorwad references. AJso

no iniormalion aboul th€ type olthe erpression is inhedted by the symbol,

which meanslhey are nol always lhe best choic€ in code using seclions,

eg. section Code,Text

Marker

;This next line will9;6 an eroras'is l€lative to ihe start oithe seclion and

;Ma erisjusta number

;ll Maker is derin€d wilh an EOU ihe €xpression willevaluale.

dcb.b '-lvtarker,63

Strlno Eduates

EOIJS

EQUS is used lo assign a value lo a stdng variable. Stdng var ables are

used lorihings like version and copyight messages oras scralch va.iables

As symbols .quat.d silh lhe EOUS direciive can be used anywhere in your

code they must b€ preceded by a backslash 0) character so the assembler

knows thal a sldng equale is lollowino. ll ther€ could be conlusion as to

whers th€ name orlhe strino variable ends use a second backlash as a

delimiler. The only exception lo lhis rule is in expressions, as il ths

assemblerlinds a symbolwhich is a slfing va able whilsl evaluating an

expresslon. th€n lho stdng is substiluled automalically.

The parameter 10 the EOUS directive will usually be delimited by quoles in

which case thal lexl is assigned lo th€ sting 6qsate. ll the quoies are

ommitled lhe ass€mblsr expecls the parameler to b€ ths neme ol an already

dgrined slfng €quate,lhe conlents oJ which are tlansfered 1o lh€ new stdng

The parameter can also b€ enclosed in cudy brackets ({}) lh€ use ol this is

explained in the seclion on macros.

Examples

dc.b

i dc.b

€qus 'Demo VeEion 0.21 22105/89'

IDA

; Note use ol second backslasi as delimit€r

'D€mo Version 0.21 22105/89'

'lnlDispAddr'

\IDA\1

lnlDispAddrl

\IDA\2

lr DispAddr2

; expands to

; erpands to

dc.l

HexSlr

; exPands lo

, her

hex \Hexsti\Hexslr : Note lwo backslashes

FFOOEFOO

Sldngs are delimiled with quoles, single (')ordouble ('). The quotes which

are used lo delimit the stdng aner th€ EOUS direclive do nol become part oi

the symbols conlents.lryou want to pul asingle quolo in lhe string yor.r can

eitherdouble up the single quolo ord€limil the sidng with double quot€s.

Exadly ih€ same applies 10 double quotes: eilherdelimir wirh single quotes

Examples

Singlel

Single2

Doublel

Double2 equs

1t's great'

"l1sgrcaf'

'They shouted "Yes ' togelhe/

"They shouled ""Yes'" logethe/'

There is a prcdefined sling equale called _lllename which holds the name

oflhe lil€ b€ing assembled- This is lhe lile on which SNASM was invoked

not lhe cur€nt includo ril€.

Exampl6 dc.b 'To rebuild lhis assemble Llilename,0

BS Eduates

RS. RSSET, RSRESET

Syntar Ss.size Count

RSSET Value

BSEESET Ualuel

RS equales are used when you wanl lo deline a sel of symbols as onsets

inlo some data struclure bul do not want 10 keep track ol the ollsels yourcell.

The assembler has an inlernd vanabb called _FS which is ussd lo keep

irack ofthe curr€ni ofiset. When you dgline a symbolusing lne RS direclive

_BS's valus is assigned lo the symbol and lhe counler is advanced by the

speci,ied numb€rol byles, words orlong words. The RSRESET dkeclive

zeros _FS and is used al lhe start ol each new strucIure. FSSET puls any

value you like into the _FlS variable, it is used when you want to stan the

offsels al somelhing olher lian zero-

For compalibility wilh olher assemblers,lhe RSRESET dlreclive can lake an

oplional parameler. which il presenl causes it lo behave exaclly like lhe

RSSET direclive.

Exampl€s

Fil6Handle

Fil€Open 1 ; _RS=o

1 ;_RS=2

8+3 ;_BS=3

1 ; _RS=14

0 i =18 _RS is nol advanced h€re.

_RS

-8 ; -ve as address register poinls

; eight byl6s jnlo dala slructure

FileName rs.b

FilePos 16.l

Filespecsize Is.b

;or w€ could have used

Filespecsize equ

2) Issel

tWe could have used r

i rsres€t -8

; bui this is lor compelibility and ils use is discouraged

ObjXPos rs.l

ObjYpos rs.l

ObjFlags rs.w

Objspeed rs.w

lilhe auto€ven option is enabl€dthe wod and long loms oi BS lorce the

_BS variable to b€ s€t to lhs ne{ even bourda.y bsrore ihe operation is

L,se oi RS and associated direclives rssults in dae$ruclure d€finitions thai,

in addiiion to being easy to read, allow you to acld or subtract fields without

having lo count on yourlingelsl

Pr.-d.flned Constantg

To help you ke€p lEck orwhrch velsions ol your prog.ams were made

when. SNASM6SK prcvid€s the lolowlnE pre.defined numeric conslanis.

Narog

-YEAR

-MONTH

-DAY

-WEEKDAY

_HOURS

_MINUTES

_SECONDS

Exampl6

AsmDay

Noles

The above conslants holdthe date and time ai the slart ot assembly: iheir

valugs do not change dudng asseobly.

To put lle dale and time inlo a slring yo.r can use lhs \# parameterwhich is

described lal€r in the cha er on Macrcs,

Faolsler eosaieg

EOUB

EOUR is osod to deline a symbolas a synonym tor a data o. address

rcgisler lo improve code readability.

Gr€goian (e.9. 1989)

1=January... l2=December

day

Example

; @uld be wnllen as :-

Powsr equr

CelDataRr

Curlndex

move.w d0, Ofls(a3d2.w)

€qur a3

€qur d2

;"r"." Power,Oits(CaDelaPlr,Curlnder.w)

Dols ars not pemitt€d in the nam€s ol regisier equates so that the

assembler knows lhal Cudndsx.w m€ans the low€rword ol {d2) ratherrhan

a register €quate called Curlndex.w.

BKi

Simila y BEG is used to deline a sy.nbolasa synonym tor a tisl otdala or

Erampla

movem.l d0-d6/a0.a6..(sp)

:could be wrinen as :-

MainR€gs req d0{6/a0-a6

movem.l MainRegs,-(sp)

Detining Data

Dellnln9 lnltlall..d Oala

D.a

The DC dkeclive takes a variable number of argumenls and all€r evalualing

thsm places lhe results in lh€ objecl code in eilherby,le, word or long word

Examples

LineLengih

Signalure

ExelD

EnorNum

Erolstr

Dispatch

llyou wanl to pul asingle quote (') in a$nng you can eitherdouble up the

single quote ordelimillhe slring with double quotes ("). Exaclly the same

applies to doubl€ quoles: €ilher delimit wiih single quoles or use lwo

-69,202

SldngBufisr

'zM'

'Maximum length exceeded',o

Rouiinel,Rouline2,nouIne3

dc.b

Syntax DCB[.size] count,value

The DCB directive is used lo generate a block o, memory conlaining a

specitied numberof instances olths sams byie, word or long value.

Examples

dc.l

dc.b

dc.l

Examples

Singlel

Singl€2

Doubl€1

Double2

DCE

'll"s greal'

"ll's great"

'They shouied "Yes" rogether

'Th€y shouted '"'Yes"" togethe/'

100,63 ; 100 byles containinq 63

256,7 ;256 wods coniaining 7

dcb.b

l{lhe auto.even oplion is enabl€d lhs wod and long lorms ol DC and DCB

iorcelh€ program counlerlo the next even boundary b€lor€ lhs operation is

Whereas some assemblers lruncate out ol range parameters 10 lorce lhern

inio rang€, SNASM6SK gives an srror

e.g. Allollhe following cause an eroi:-

dc.w -40000

dc.b 260

dc.b n30

Handv tio

llyou detineWod and By.le as shown below you can uss lhsm as a quick

and r€adable way of lruncating a numb€rto a word or byle.

70000 greater lhan 65535

less ihan .32768

grealer the 256

less lhan 128

Byte

BigNumber

'$FF&',

70000

\Word\-40000

(h.b

e.g.

MaskTabl

i could b€ wdllen as...

MaskTabl hex

\Word\BigNumber

\Byie\(-80'9) iBrackelsareimportanll

\Byie\aigNumber

EEX

The HEX dircclive is followed by a slream ot hex nibblss which are paired-

uP lo givs byles.

The HEX direcliv€ should only b€ used lorsmallamounts ol dala. Dala

stored as h€x is very unr€adable, takes twice the space ol blnary dala and is

slower to load and assemble. Ratherthan having vast quaniiiies ol hex data

you may preler ro pul lhe data into a iile as raw byles and use the lNcBlN

directiv€ d€scribed laler

DATA and DATASIZE

The DC dir€ctiv€ can only be used lorconslanls that can be contained wlhin

32 bils, lt is somslimss n€csssary lo plac€ larger conslanls wilhin code and

the DATA and DATASIZE direclives havs b€en provided lorthis purpose.

DATASIZE is lollowed by e single paramelerwhich speci,i€s how many

bytes are lo be used lor conslanls delined using the DATA directive. The

DATA dirocliv6 has avariable numberof parameters, which are decimal by

delaull bul which can b€ hex il pr€ceeded by a dollar ($). Binary numberc

and the altemate numefic lom cannot be used.

dc.b $01,$02,$04,$08,$10,920,$40,$80

0102040810204080

Erample datasize I ;256 bil numbeE

dala 10000,1000000

dala $100,-200

data 200000000

B.servind S.ac.

The DS dirocliv€ is used lo iese e, and inilialise lo zero, a block ot memory.

€.9.

ScrarchBuiier d5.b 1000 ;space for 1000 bytes

Pointetist ds.w ,6 ; space lor 16 wods

lrlhe aulo+ven optlon ls enabledlhe word and long word lorms o{ DS lorc€

the program counlerlo the nen ev€n boundary belore lhe operation is

performed.

The OS dir€clive is used in BSS lyp€ sections 1o reserue space. Uke

€verything in BSS sections no inilialisalion is p€rlormed, so don't rely on

there b€ing zeros in menoryl

Changing the Program Gountel

cre

OBG ls used to telllhe assembler wh6re inlhelargot machinelh€ cod€ is io

reside. You sholld.ol use the ORG directive ilyou ar€ producing linkable

oulput as tha linker decjd€s whgr€ th€ vadous parls o, lhs program are lo

go. ll you ar€ nol using seclions in your prcgram you are lres io us€ as

many ORG dirsctivss as you wish.

Erampls

Slartl otg $400

lea lvrstack,sp

lf lhe argumentlo ORG sla(s wilh a qu€slion mark (?) n as inrelpreted as the

amount of RAM lh€ prcgram fleeds and the targel is asked to reserue lhat

much memory, Ths targ€tthen returns ihe sddress al which it managed lo

rcsevs th€ RAM and SNASM6SK assemblesthe pogram to run al that

Example org ?512',1024 ; asklor 5l2K ol Ram

Slart l€a VaBase(pc),a6

This lacility is us€rulwhen developing lora macnine wilh the operating

systsm resident. This lorm ol the OBG darective can tak€ an optional second

palamel€rwhich indicates the lype ot memorylo b6 resorved, Th€ value of

this parameler is specilic to lhe velsion ol lhe larg€t soltware being used.

EYEN

The EVEN direciive lorces lhe prcOram counter lo lhe n€n even address.

Example

Prompl

; Butsr musi be on word boundary

1024

'Hit a key when ready',o&.b

BuJl€r ds.b

cloe

CNOP sets lhe program counierlo agiven olrs€t rrom any size boundary

Examples

cnop

o,2

o,4

64,128

; same as even direciive

; nexl long word boundary

; 64 byles above next 1 28

; b).le boundary

Wh€n using seclons il ,s noi possible lo align lhe prcgram counier to a

larger boundary ihan lhe aliqnmenr ol the cureni s€cton, i e. EVEN cannot

be used in a byte aligned seciion and CNOP lo a 4 byles boundary cannot

_ be us€d in a wod aligned section.

OBJ and OBJEND

- All code g€nelalsd an€rlh€ OBJ directive but before lhe OBJEND dk€clive

willslillbe placed at thesame place in memory bullhe code wjllhave all

ollsels sel lor il lo run at th€ address specllied alter the OBJ dk€ciivs.

ThiS is sometim€s reJored to as asssmbly with otlsel.

Exemple oQ $8000

RunAddr equ $400

-. l€a Reloccode,ao

lea BunAddr.al

*(RelocEnd-Rotocoode)/2-1 d0

@Loop move.w (a0)+,(a1)+

_ dbra do,@Loop

jmp Retocoodo

Reloccode obj RunAddr

; EveMhing within this section willbe set to run at RunAddr

jmp Slarlup

$anup .ou".,, *$z7oo,sr

obi"no

RelocEnd

OBJ and OBJEND should always be paired correcity it you need lo reverl lo

'normal assembly, Dont ommil an OBJEN0 diecliv€ or use lwo otthem, or

aflempt lo nest OBJ/OB.,END pairs, as the assembter wilt toose track oi

where lhe PC acrually is, and no doubl you willlool

lncluding Source and Binary

INCLUDE

You will almo$ ceneinly wani lo break yosr source code into several smaller

_ ,iles eilhsrlo make il more manageabl€ orso you can lse some olthe pans

in more lhan one program,

The INCLUDE direclive tells lhe assembler lo proc€ss anotherfil€ belorc

- continuing wilh lhe clnenl one. You will nomatly heve one rool' ,ile which

includ€s all the olher parls ol your cocle. ll you wanl, lhese includ€d ril€s can

include liles of their own.

Example

- SlarlupCode jmp MainEnlry

include 'equs.asmr

includ€ c:\general\malhs.asm

MainEnlry lEa Mystack,sp

lllh€ lext lollowing the backslash can be conlused $ith asling equate use

eilher lwo backslashes or a lolward slash. You may encloselhs file spsc. in

quoles if you wish bul lhey are optional.

e.g. include c:\\general\mAhs.asm

- includ€ c/general/maths.asm

ll lhe fil€ c€nnot be found in lhe cu ent direclory it is searched,or in all

dkectoies specilied wilh the 4 sw1ch.

- tNcEtN

l, you have a lot ol data in raw binary romal such as graphics or music dala,

you oan us€ the INCBIN directive lo include lhis into your prooram. As the

_ daia is jusr byres the assembler knows norhing abour its inlemat slruclurc

and you will have to put a label on the dala and handl€ ot sets into lt

yoursell.

Exampte

- lea SineTable,ao

add.w d0.d0

add.w d0,a0 i lndsx wods in sine iabte

- SineTable iii"Uin 'c:\labres\sintab.bin'

See the abov€ notes on using backslashes in palh namss,

tlthe lile cannol b€ round in the curenl directory it is ssarched for in att

dirccloies specilisd with the /jswitch.

lfyou needlo know the size ola binaryllle bofore you includs il then you

can uselh€ FILESIZE ,unclion. This retums lhe size ol alile in b).tes or

minus one il lhe lile ennot be lound

Ex.mpla

EinHeader dc.l

lncbin fileslz€('sinlab.bin)

sintab.bin

DEF and REF

ll you havo a gsneral purpos€ piece ol source code that will b€ includod in

quit€ a lsw projects you oiten want to have conlrol ovgr e)(actly which

routines ar9 included, Tle REFoperalor relums true ilthe symbolfollowing it

has already been relerenced,

Erampla il rel(Prirn0

;This is only assembled il Pintf has been rer€r€nced

Pnn movem.l do/ao.-(sp)

; end oi pinll rts

Th€ DEF operator returns true illhe symbollollowing ii has already been

delined. You can us€ lh€ DEFtunclion lo ch€ck illhe va able has akeadv

been delined and lhen detln€ il only i, n€cessery.

Example il -del(SlfingBuller)

; This is only assembled if StingBuff€r hasnl been delined

SldngBullei

EEE

The lype lunction provides inJormation about a symbol. lt enabtes a macro

to delermin€ exactly what il has b€en passed as a parameier.

The valug retumed is a word, wilh the bils having the lollowing meanings :-

ds.b 64

endil

Sel il symbol has absolule value

Set llsymbolis relalive lo slan ol a section

Sel il syfibol was derined using 'SET' direciive

Sel il symbol is a macro

Set if symbol is a sldng equals

Sel il symbolwas derinsd using an 'EOU'directive

S€t il symbolwas specalied in an'XREF statement

Sei ilsymbolwas sp€cilied in an'XDEF nalemenl

Sel ilsymbolis a tunclion (STBCMP, NARG elc.)

Sel il symbol is a group name

10 - Sel ilsymbolis a macro paramstsr

1 1 ' Sel i, symbo! is a shon macro (MACROS)

12 - Sel ifsymbolis a seclion name

13 - Set il symbolis absollte wod addrsssabl€

14 - Sel il symbol is a r€gister equal€

l5 - Sel il syrnbol is a register lisl equale

To check specifc bits roturned by th€ ryPE lunclion use the bitwjse and

operator (&).

Erample

ir 0p€01 )&$200)=0 ; ch€c* bit 9

inlolm 3.'y"s is nol a grcup name!',\1'

endif

Setting Target Parameters

BECS

ll you are silhsr ssnding cods straight lo the taeel machine or il you are

producing a CPE fil€, it is possible to specily the values lhat you wanl the

68000 regisleB to have wh€n your code is €x€culed, lJsually lhis leature is

used tosetlhe Pc at which you wanl €x€cution to begin, andlhevalue of

SR ar rhis rime.

Example

org $400

regs pecodestan,sr=$2700

Codestad lsa Myslack,aT

As the 68000 has two slack poinlsls you must use be speciiic about which

- you mean by using USP and SSP.

This lealure cannot be us6d ilyou arc producing machine specilic

.elocalable or pure binary formals.

WOBKSPACE

Ths laEel solware uses about 1 K of memory ,or its own workspace. Wiih

mos! versions of th€ larcel sollwars il is possible io change ihe address ol

_ rhis usinq the WORKSPACE command.

Example wo*space $80000 ; above 512K

- :: ${00

Assembly Flow Control

END l€lls the asssmbler lo immedialsly stop processing lines. The usg ol

END is onliroly optional as SNASM68K aulomatically stops when lhe €nd ol

lhe source lil€ is reached. END has an optional parameter which can b€

used lo sp€dt ihe ex€oiion address ol lhe prog,am. Use ollhis f€ature is

discouEgsd asihe REGS dircclive can t€ used lo achi€v€ that sam6 ihing.

Erample3

Slanupcods lea

;;

; End of proqram end ; No sian address

No enor here as lhis line is never reached.

lvrSlack,sp

Slartupcod€ lea

jmp

end &anupCode ; slat al slartupcode

lF ELSE ELSEIF and ENDIF

Th€s€ ar€ ussd lo conlrol€)(aclly which lines ol code get assembled.

Conditional assembly is us€lulilyou need to generale severalversions ot

lhe program, but il is mainly us€d in macros lo c€lse lhem to expand

diff erenlly under dillerent condilions.

Exslnples

DebugMode

equ 0

equ Falss

;The lollowing cod€;ill be skipp€d il D€bugMode is lalse

it DebugMode

move.w XPosilion.do

Fr Pdl

endif

English

i Assemble correcl;;nk odenng sldng ac.oding to qrrr€nt language.

il Lanquage-English

English

German

Language

equ

dc.b

ifdc.b

endil

equ

tAssemble corrocl drink ordoing string according lo currenl language.

dc.b

€lse

Two b€ers pl6as6',0

Language=Fr€nch

'D6ux beir silvous plait',o

Language=Geman

'Zw€i bier bitle',o

Language=English

'Dsux beir sil vous plait',o

Language=German

'Zwei bier bilte,0

English

Languag€

English

itdc.b

dc.b

€lseil

dc.b

Ngles

ln example ihree th€ ELSEIF direclive has been used lo make th6 cods

more readable. ln lhe same example ENDC is ussd inslead ol ENDIF to

show thal they arc synonymous,

For compatibilily wiih other assemblels lhe ELSEIF direciive can be lsed

withoui any paramelers in which cas€ il acts exactly like an ELSE dircciivs.

lndenling ol code has been used in thss€ €ramples to male tho cod€ more

readable. You may wish lo do the sam€ rhrng bul ii is €niir€ly optional.

The logical not (-) op€rator can be used lo branch on lhe opposite ol a

condition bui you musi be car€tullo parenlhesiz€ the €xpression corectly.

e.g-

;ll may be templinglow le

il -Language=German

; bul you probably wanied

ll -(Languag€=Geman)

CASE-aod INDCASE

lf you hav6 a symbol which you wanl to nse lo saleci b€iw€sn sev€ral piecss

ot code as in €rampl€ lhr€€ abovo,lh6 CASE directive can bo used. This

dkective can be used in place ofthe lF direclive as shown in example one

below, bul ii really comss inio iis own lormulti'way choices.

Syntax CASE Expression

=Expression{,Expression)

EN DC ASE

True

LargeBull6r

256

1024

Example3

True

Larg€Butf€r

=True

equ

ds.b

2')

i A6sembls corrscl ddnk ord€ring string according lo cur.snl language.

English

German

Language

-English

€qu

dc.b

English

Languag6

'Two beers pleass',o

'D€aux bek sil vous pleil',o

'Zw€i bier bifle',0

ExeculeMod€ €qu o

DebugMode equ 1

SaveMode €qu 2

ProgMode equ SaveMode

;;" ProsMode

=ExeculeMode,D€bugMode ;Selecloneilhervalue

l6a l,lystack,sp

jmp Codesiarl

=SavoMode l€a Codeslart.ao

mov6q #0d0

move.w #Codss€cis,dl

jsr Wnleseclors

rls

=? Inform 3,'Bad valu€ lor ProsMode'

; See laterinlhis manualtor etplanalion ol INFORM

6ndcase

NglEs

The =? cas€ is us€d il non€ o, the olher cases succeed, ll lh€r6 is no =?

cass and allths oih€r cas€s lalllhen non€ ol lhs cod€ will b€ assembled.

BEEK!4ENDE

The REPT direcliv€ is used to repeat a shon soclion olcod€ a

prsdel€min€d number o, times.

Syntax HEPT Expr€ssion

ittoa

Eramples

1) r€pl 16

mov6.w d0,-(a0)

endr

Tabl€Enln€s equ 21

lnd€r = 0

repl TableEnldes

clc.w lnd€x

lnder - lnd€x+64

endr

WHILE .nd ENoW

Th€ WHILE dkecliv€ is us€d 1o repeat a short section o, cod€ whilsl an

exprcssion evaluales lrue,

Syntex WHILE Expression

- Exow

Eremple

Factor equ 4

i Build lhe code r€quired 10 muhiply by laclor

T€mp - Factor

whil€ Templ

rol.w (s0)

- T€mp = T6mp>>1

€ndw

DAi[d]]NIlL

Th6 DO/IJNT|L loop is similar to lh€ WHILE/ENDWH|LE loop excepl th€

condiiion is checked al the end olths loop andthe toop,ng tinishes once the

condilion b€comes lrue.

- Syntax DO

iixrt Expression

Example

Faclor equ 4

I Build lhe code rsquirerl lo muliply ry laclor

Temp = Factor

rol.w (a0)

* Temp - Temp>>1

until Temp<=1

Macros

A macro is a way ol giving a sequence ol assembler lines asymbolic name

so they can be assembled lal€r as many limes as you require, A macro is

invoked es il it wfiere a new direclive and like dk€clives param€l€rs can be

passod lo them. They ar€ used to ext€nd ths ledtures ol lhe assembler or

jusl save a bil of tyFing.

lntroduclnd llacro3

MACRO and ENDM

Th€ lines b€tween the MACRO and lh€ ENDM dk€ctives are stored an

memory and can b€ relerenced uslng th€ label proc€ding th€ MACRO

Example

; Expands to two NOPI

Delay

nop

TwoNops ; assemble lwo NOP!

TwoNops ;lwo more

WheneverTwoNops is used as if il wer€ a dirccliv€ lhe macro is expanded.

MEXII

Th€ MEXIT dksclive causes expansion ol ihe currenl macro lo slop

immediately.

Exemple

;Macro $lrich repeal a stdng acedain numberollimes.

NewDs macro

inlorm

mexit

€ndit

natg<>2

2,'Wrong numbsr of parameters

repl u

dc.b \1

€ndm

NewDs 'Hello',2

lhe MEXIT direclive is supporled lor compalibilily reasons as the

above could be vwitten much mors neally using rhe lF..ELSE..ENDlF

lllcro Peremeter!

A macro can lake parameters which can be used any,u/here in the macro

iu$ as (lh€y w€re sting 6quaies, i.e. prec€dsd by a backstash (\). Again it

there could b€ arry conlusion lh6 parameter c€n bs temrnaleo wilh another

backslash.

Ther€ can b€ up to thidy two param€i€rs, \O to\31 wiih \O being the size ot

lh€ macro,.e. rhe t€xl l6lrowirig th€ dol (.) , any, when lhe mairo was

invoked-

Erample

I Macro io increm€nl regisie.

lnc addq.\o #1,\1

endm

lnc d0 expandslo addq. #1d0

the assembler ignores the doi

expands to addq.b #1.d1

expands lo addq.w #1,d0

expands io addq.l#1,d7

:Macro!o branch il rsgisier notzero

BENz ts1.w \1

bn€.\o \e

endm

BlaNz do,Exit

BraNz.s dT,Again

I ll you €nclos€ an argurne in angte bEckets (<>) you can us6 spac€s and

r 6mm.ain n

Format macro

dc.b 13,13,'\1...,,0

endm

Foma

lnc.b dl

lnc.l d7

SHIFT and NABG

ll is oJten ussrullo have a macro which takes avaiabte number ol

parameleE. Th€ pr€delined NARG symbot and ihe SHtfT direciive a,e used

Io delsm:ne how many paramelerslhsre are and nep ihrough ihem Shirl

causes \1 io b€ losi and shrttslhe resto h€ parametarc dow-n so th€ \l

b€comos what \2 was etc

Example

;Macro to DC the given parameterc ait€r doubling them

DCtz macrc

repl nars

dc.\o V'2

shilt

endr

endm

iiC,e.* 2,8,9 ;lhswords4,'16and lsareDC?

S€€ ihe descn ion of €xt€nded macro param€tors lor mors uses ol SHIFT

and NARG.

Named Macro P.ramel.ri

ll you prefer you can assign symbolic nam€s lo the macro paiamelers lo be

usd inslead o, \1 10 \31.

Examplo

Scale macro X.Y.Faclor

dc.w Uc\Faclor,\nFaclor

endm

Shorl ilacros

MACROS

Nomally controlslruclurcs musl be propedy n€sled wilhin macros. ll you

stait a slruclurc in a rnacro you musl inish il belore lhe ENDM and €qually

you canflot terrninale a structur€ thai you didn't stan in that macro.

You may occasionally when porling code from othsr assgmbl€ls, n€ed to

delins macros to imilate conl,ol struclures. Shon macros coniain only a

single line ol cods, bul this line can be a control structure direclive it you

Erelnples

iMacro lo implementthe lFEo (il equals) conditjonal

if€q macros

it \1=0

i Nole: Short macros donl have an ENDM

ileq DebugMode

inair

; Macro to implem€nt the IFNO (il not defioed) conditionat

ifnd macrcs

il -del01)

ifnd Count

Counl dc.w 0

endil

Nol€

lf the,k command lin6 oplion is used lhe abovs macrcs are automaticatty

defined along with several others.

ErtEndcd Pel.meters

SNASM68K allows you to pass a list oi ilems €nctosed in cudy blackels (0)

lo a macro paramet€r.

The NARG symbol has been exlend€d so lhat it can repo( how many ilems

have been assigned lo a parameier and sim ady SHTFT can now be used

Exampla

Black equ 0

Green €qu 1

Red €qu 2

; Macro which takes colourc and point lisls

;e.9.

; Black,{0,2,3},Green,{0,3,6,8},Red,12,4}

; and gen€ralos dala conlaining the colour,lhe counl ol points and

; th€n lhe point dala

;e.9.

; dc.b Black

i dc-b 3

I dc.b 0,2,3

: dc.b Green

: clc.b 4

: dc.b 0.3.6.8

: dc,b Red

- tdc.b2

;dc.b 2,rl

PolygonLlsl macro

Polygons\@ = narcl2

; Check narg was ev€n

if polygons\@'2onarg

inlorm 2,'Bad parameter list

- else

; Handle all polygons

rept polygons\@

dc.b \1

points\@ = narg(2)

dc.b points\@

rept poinls\@

dc.b \2

shifl 2

€ndr

shili

.- shin

dndr

endil

_ endm

;ovgonList Black,{0,2,3),creen,{0,3,6,8},Bed,{2,4}

The abov€ erample may look complex bul note how alllhe complexily is

- hidden away inside the macro and how neat the main code took.

For compalibilily with olhsrassemblels il is possible lo equale a symblto a

Examplo

Delltems

Dav

list ol paramelers using EOUS and use NARG and SHIFT on the stnng

equale €xactly as they werc used on lhe macro parameler above, This

,ealure allows the macro to accept lisls o, arg!menls using angle brackeis

instead of clrrly brackels.

rspt

dc.b

shift

deftems <'Mon',Tue','wed,'Tiu','Fri','Sat','sun'>

i normally we would hav€ used :-

Delllems {'Mon','Tue','Wed','Thu','Fri','Sal','Sun'}

C6nllnuatlon Lln.s

lf when you are invoking a macro, th€ lins becomesvery long, you can

lerminale th€ llne with a backslash N, and continue lhe list ol paramelers on

Erample

DoubleT

t1)

nars(Day)

\Day,0

oay

dc.w \1'2,\2'2,\3'2,\4'2.\5',2.\6'2.\7'2

Dou bleT 1 1 1 1 ,2222,3333,4444,5555,\

6666.7777

Label lmporrind

A macro can impoi th€ label on lhe line on which il was invoked and use it

iust like any olh€r parameler. The lab€l is not delined ro be al lhe current PC

as usually happens, in lact, unless the macro specilically assigns a value to

lhe symbol in some way il is undelined,

To l€ll SNASM6SK that you woutd tike to use tabet imponing you must

specily use astensk {') as ihe fiIsi named macro parameier, ihen you can

us€ \'to substitute lorthe label-

Example

;A Macro that assigns labels relativ€ to the slan ot a dala labte.

BC macro ',Dala

€qu '.var8as€

repl narg(Dala)

dc.\o \Daia

shift Data

endr

VarBass equ

rc.w |'1,2,3,41

rc.w {5,6,7,8}

i; va€ase{pc),a6

move.w Ll(a6)d0

Advrnced lrecro Feetur.s

PtISHP and POPP

_ SNASM6SK l6ls you push some rerl and taler pop it into any sling vadabte.

Exampte

; DC palam€lels in revorse oder

BackDC macro

- local temp

; Push lhem all repl narc

- pushp \f ipush text contents ot\1

shii

€ndr

I now pop and OC them

- rept naru

popp lemp ; pop lsxi pushed ea ier

dc.\o Uemp

sndr

endm

i;ackDc.w 1,5,7,E

_ You are not restricted lo poping the parameler in lhe same macrc that

push€d it. Ihis allows some very ffexible maoos 1o be wdtt€n lo handte s€ti-

reler€ncing data slructures.

nrnind numbers into sttinos

The\*and \$ paEmeteB substilute the decimat or hex vatue ofa symbol

inlo your cod€ al any polnl. They are used lo lum oumbers ido *nngs lor

lomattlng dala or blrildin€ arrays o, symbols.

Eral'lptet

. i PlJt lhe (hta and llmo lnto a sldng

AsmDale clc.b 1#-dayl#_monlh^#Jea/

; oQands 10

AsmDate dc.b '13/121989'

Colo 6qu $FFF

Coll equ $FoF

Col63 equ SoFF

- Col99 squ $FFo

Index = 0

dc.w CoA#lnd€x ;€xpanG lo Colo

lndex = 1

dc.w Col\#lndex ;etpancls to Coll

lndex = 99

_ dc.w Col\#lnd€x ; €xpands lo Col99

dc.w Col\$lnd€x ; €xpands to Col63

iThe words DCd will be $FFF,$F0F,$FF0 and $oFF.

Unloue Lab€ls

There is a special macro paEmeter \@ which expands lo an undeE@rc

_ lollowed by a d€cimal numb€r which increments upon sach macro

invocalion to guaranloe uniqueness.

Exemple

Delay macrc

- move.w \1.U

Loop\@ dbra \2,Loop\@

€ndm

- D€lay #3,d0

Each time lhe macrc is €xpand€d a dift€reni labelsuch as Loop_000 or

Loop_300 will ba generaled.

. zuBGE

Macros can take up a larce amoudl of m€mory and sven though

SNASM6SK stor€s macros very €fticJenlly th€y might as w€llbe r€movsd if

- lhey are no longer needed. The PURGE directive removes a macro lrom lhe

symboltable and fre€s up the memory ll was using.

Ex.mple

SigMacrc mecro

iino'

; Code that uses BigMaco

BigMacro 1,2,3

purge BigMacro

; BigMacro now no long€r exists and can b€ rsdefrned if we wanl_

ll a macrc puEss itsolf, tho delinhion ollhe macro ls not rcmoved untilthe

macrc exits.

- tl you jusl want to red€fine a macro lhere ls no nsed lo purge il when a new

derinilion ollhe macro is encounter€d th6 old macro is automatically purged,

A macro can, i, you really want, r€define its€ltl The new delinilion wilt be

eflectiv€ nexl lime lh€ macro is irvoked bul does not inter,erewiih the

expsnsion ol lhe currenl invocalion,

ExEmple

StranEs

- inlorm o,'H€llo,

Slrange macro

inlorm o,'GoodBye'

€ndm

$renge

€ndm

6i'"ns"

Strange

This will oulpul :.

H€llo

GoodBye

String Handllng

SNASM6SK provides some uselulsling handling funclions and directives

whlch arc used (usually in macros) lor comparing. searching and slicing

sldngs.

slEtE!

STRLEN is a lunction lhal can be us6d anyl here in an expression and

which relums the lsngth ih characl€G ol its stdng parameter.

ExahPle

; Macrc to DC stdng precsded by ils tenglh

- Stdng macrc

dc.b strl€n01),\1

6ndm

String 'H€rro'

slEct P

Synta,

symbol = strcmp(slringl,stringl)

STRCMP is a lunction thal retuhs a boolean vatue (0 ror fatse, -t lortrue)

which i6the result ol compaiing its two stdng paramel€rs.

Erampla

Language equs 'English'

;Assemble correct ddnk ordering sting according to curent language,

- if slrcmp{lLang uag€ ,'Engtish')

dc.b 'Two beers pleas€,,o

else

il strcmp(\Language','Frsnch')

dc.b 'Deux beksilvous plait',o

€lse

if strcmp(\tanq0age,,,G6rman,)

dc.b 'Zw€i bier biie',0

endif

endil

endit

INSIE

Synlax

symbol = lNt(lstad,lstnng,sub-sl ng)

INSTR is used to s€arch a siing ro see it it contains a sub-stdng. tfthe sub,

string cannot be lound the rcsul is 2ero othelwjse il is the ofJset into the

stdng thal lhe sub-sting occu ed. Here as in all or ihe slring commands the

lirsl characlgr in lh€ sting is character nlmber 1 .

Erample

i S€i DebugMode i;e veBion ging conlains the word l€st

il instr(1velsion','test,)

DebugMode - -1

else

DobugMode = 0

€ndi,

INSTR5 oplionallilsl pahmeter is rhe position from which to slart the

subslr lsiart],lendl.slfi nE

SUBSTB rs s,mJarro EOUS in rrar I rs a way or doing a sinng equale

\owever allows lhe slan and end characl€.s olthe 5r.r9 io be specitied.

Example

TestSlr

Templ subst 6,9,1T€n$i

iTempl will equal'does (without lhe quot€s of couGe)

Temp2 substr ,4,\Te$$r

; Temp2 will equal What

T€mp3 subslr 6.,1Te$$i

; Temp3 will equal does this do?'

SUBSTF

Synlax

'lntemal iest version 0.9'

equs 'What does lhis do?'

Local Labels and Modules

Wh€n you ar€ writing a large program il becomes very hard to lhink oi an

inlormalive and uniquo name ior €ach label . Local labels help solve lhis

problem as lh€y only o(ist wilhin an area called rheir 'scope' and lhey can

be r€-used oulsid€ lhis ar€a. They ar€ mainly us€d within routines as 'place

ma*ers ,or shps and loop€ whor6lh€re is no ne€d for oth€r routines lo be

Local labels hav€ afl al sjgn (@) as lhei.lirsl chaBcler and lhis is lollow€d

by an valid label characlers.

Erampla

I These are all local lab€ls

@Lab€l

@L1

@123

SNASi,6SK has two ways of conlrolling the scope ol local labels. ln the lirst

ol these a loc€l label's scope extends belwsen lwo non'local labels.

Exampl6

lncNzD0

@Nolnc

lncNzDl

@Nolnc

tsl.w d0

bne-s @Nolnc

addq.w #1,d0

bne.s @Nolnc

addq.w #1dl

rls

The local label @No lnc can be re-ussd as it's scop€ is between lncNzDo

and lncNzDl.

This iorm oi scidng is supported lorcompatibiliiy r€asons and it is nol

MODULE and MODEND

SNASM6SK has anotherscoping system which can b€ ussd ireely wilh the

above scheme and which giv€slhe progEmmer much more crnlroloverthe

Code which is belween MODULE and MODEND directives is said lo

compiss a module, A local label delined in a modul€ cannot be relerenced

oulsde lhal module, and can be r€-used lr€ely. Equally .ny local labels

d€fin€d oulside lhe module cannol be r€Isr€ncsd within it.

Erample

CleaDala

@Loop

module

bsr @Clearll

dbra d1,@Loop

rls

clr.b (a0)+

dbra d2,@Loop

rts

@Clearn

@Loop

;end of @Clearll

; A rclerence to @Loop would rcler lo lhe lirsl deiinition as we

: are back in the module ClearDala,

modend

i snd o, ClearDaia

A label js assumed lo b€ inside a modul€ if it is declared on any line alter the

IVIODULE direclive uplo and including the lin€ on which the MODEND

Orlslde modules ths'belween non-locals' scoping is in ,orce fui it is wonh

noling lhal a module is trealed lik€ a non'local and defallr scoping is

block€d by il.

s.g,

:This will nol wo* unl€ss it is all €nclosed in a mod]lle.

@Loop movem.w d7,1sp)

@SubModule moaure

modend

movem.w (sp)+,d7

dbra d7,@Loop

The assemblsr willgivs an ermronlhe last line ofthe above example aslhe

DBFA is not within @Loop's scops.

Macro sxpansion has no ellect on the scoping oflocallabels, Any local

labels which exisls in a module can be relerenced wilhin a macrc expand€d

in lhal module. Ilyou wanl a macro lo have ils own locallabels you can

eitheruse a module wilhin the macro, use lhe\@ parameteroruse the

LOCAL dir€ciive described below

The use ol modules is sfongiy recommendsd as lhey serve 10 neatly

'€ncapsulate' roulioes and rigidly detine where lab€ls locallo roulines can

and canl be relerenced.

LOCAL

The LOCAL dircclive is anolher way oJ declring labsls within macrcs. Any

symbols d€dar€d wiih the local dir€clive can be Lrs€d as if they were norma

symbols but thsir scope is limt€d to ih€ cuned macro.

Erample

D6lay fiacro

local Loop

move.w \1,\2

Loop dbra \2,Loop

endm

Localdoes nol lype lhg symbols it dsfinss, You can go ahead and declare

them as lab€ls, le( equales or whal€ver you iik€,

e.g.

Demo local Skip,Slngl,Glavily

bra Stip

Slring, equs \1\\2' ; Sting squaie

Gravily equ l0 iNumefic eqlate

Skip ;Label

endn

Options

SNASM6SK has sovetal opiions which can b€ controlled either wtlhin ths

program or {rom lhe command line. See lhs s€ctiofl on command line

syntax lor iniormalion on selling assembler options on the command line.

AEI

The OPT dirsclivs is used lo set lhe state o, th6 assgmblers options trom

within the source code.

Dcladl

olf

ofl

oll

oit

oll

off

otf

ofi

otf

olf

oll

olt

; Enable all oplimisations

opl o2+,os+,ow+

; Turn otl aulo-ev€n and warnings

opt ae-,w-

Alternatively the /O swilch can be used lo sel lh6se opiions on lhe command

lin€, ss€ lhs eadiersection on command line syntar.

AE - Aulomatic Ev6n

Wh6n this option is enabled word length dala directivess force the program

counler lo lh€ nexl wod boLrndary belore ihey are execuled. This appties lo

lhe wod and long word lorms ol DC,DCB,DS and RS.

AN ' Altemale NumEdc

Enables use ol Zilog/lntel lom ol conslanls. Seethe seclion on FADTX ior a

full cl€scriplion ol this iacility.

Assembler oplions:

AilIevialca

Optlmlsatlons:

osq

Ex.mple

Descndion

Allemate numeiic lormat

Case sensilivily

Descope locals on equ and set

Ptint source lin€ whlch caused error

Use dol (.) instead ol al (@) for locals

Treat equated symbols like labels

Prinl wamings

Allow whit6 space in operands

Writ€ local labels to syrnbol tile

PC relativ€ oplimisation

Shod branch oplimisation

Absolule word oplimisation

Zsro displacem€nt opiirhisaiion

Add quac.k optimisation

SublBcl quick optimisalion

Move quick opiimisalion

C - Case Sensitiviiv

When this is enabledlhe case oilhe lellsE in e labetb nam€ becomes

imponad. For instance you could hav6 on€ tabet catted Biglabel and

anoth€r called biglabel.

Ai-Aeselr-Lacals

Oulside modules th€ EQIJ and SET dircctives do nor usuatty atiect the scope

ol local labels. Set this oplion il you wanl EOU and SET ro descope locats.

E - Erhr I ina Printind

When ih€ ass€mbler dolocis an eror il ls report€d atong with the tite nane

and lins numberwhere il occurcd. ll this opiion is enabtad the iext ot ihe tine

lhat caused lhe €rorwillalso be pnnted,

L - Lm.! Lahel CheEcter

SNASM us€s ihe al sign 1@) as its delault toce! tab€l character. This option

changes lhis lo dol (.)

S - Tr€at aouates like labels

Wh€n lhis opiaon is €nabled lhe assembter treais e+rated symbots like

labels and wnles th6m lo ths symbollabte as such,

W'Give waminds

There are s€verallhings lhal even lhough lhey are nol errors are unusual

€nough ror il lo be wonh fie assembler repoding lh€m. tt you don,t wanr

warnings repodinE lh€n disable ihis ootion,

WS - Allow while soac6

Normally in 68000 source code comments lollow any while spac€ in lhe

operard fi€ld. This prevents th€ us€ ol iab and space to incr6ase code

readabihy io lne WS oplion has b€en added, which causes the assembt€r

10 ignore whils spac€ in operands and to insist on the use olserni-colon io

V - Wnte loels to rvmholtable

l, you wanl lo se€ local labels in lhe debugg€r then enabte lhrs opiion. To

keep lhe size ol the symboltable down you may prefsr to only tum on lhis

option lor rhe part ol lhe cods you are cunontty debugging.

OP - PC Ralaiive Oblimisation

Changes absoults long addressing lo PC rslalive addressing wherever

possibl€ and l€gal.

OS - Shorl Branch Ootimisalion

Backwards relalive branches that could uss th€ short form ev€n though you

hav€ not sp€cilied it ale used automatically if you snable this option.

O\l- Absold€ Wod Ooilmlsatlon

ll you use lhe absolut€ long addrcssing mode and the address willf anto a

wod the ass€mbl€r willuse the shoner mode il lhis option is enabled.

OZ - Zem Disolec€menl Ootimlsation

lfyou us€ the addrcss register lndirect with displacement addiessjng mode

and ths displacem€nt is zero,lh6 ass€mbler will use the addr€ss r€gister

indir€ct mode ii thls opllon is €nabled.

OAO OSO and OMO Ouick lnsrrucrion Oorimisation

Tiis oplion caus€salladd, sub and move instructions that coLtld be coded

as lho quick rohs to be coded as such. Only move.l is changed lo moveq

All ol lhe above optimisalions can only bg perlormed on backwad

PUSHO aod POPO

lfyou wantlochangethe setting olan oplion bi€tly andthen rerum ilto ils

previous value you can us€ PT SHO to save th€ cuir€nt state ot att the

options snd later us€ POPO lo relum lhem to th€ir pr€vious 9a1e.

Example

opt

dc.b

p0po

ByteSlream

; sav€ slale ol options

ae- ; lurn off auto even

456

512,80

i rsslor€ slale

Errors and Warnings

Erols and wamings are generated by th€ assembl€r wh€n€v€r il detecls

anything wrong. SNASM provides a means lorlhe programmer lo aaise

enors if an €rorcondiiion occuls whicn lhe assembler can't detaci. i.e.. a

data table becoming too lae€.

INFOqM

INFORM can 9sn6rale snors of rour different sevenles and display

messages wilh emb€dded parameters to descrjbs the eiror in detail,

Syntat lNFOBli sevedly,stiingl,op€randsl

Sevedty is a number lrom 0lo 3 wh€r€ 0 causes lhe messageto be pinled

but no aciion taken, 1 gives awaming,2 giv€s an snorand 3 causes a falal

srror where assembly slops immediately.

lltha sldng conlains 7d, %h and./.s ih€s€ arc subdnqed with the decimat,

hex or sting valu€s ol lhe opsrands in ths order that they occur.

Erample

Slrucslan dc.w 0

SlrucEnd

Struclen equ SlrucEnd-Strucsiad

if Struclen>1oz4

inloim o,'Start=%hEnd=%h',Slrucstart,Struclen

inlorm 2,'Sfucture loo long'

endil

EAIL

Fail is supporlsd ,or compatibilily and is the equivalenl ol i

intorm 3,'Assemblyfailed'

Listings

It a lislino lile name is given on lhe command line or il one is set by delauli in

the SNASM6SK environmenl vaiable lhen lhe assembler $ill generate a

listing ollhe program dunng $e lirst pass.

ll.lk!d.!O!.ir

As lislings as usually used to check how macrcs are expaMed it is very rare

thal you willwahl the whole ot yourprcgram lisied. Usring is always on al

thestan ollhe program (ila lisling fle isspecilisd). Ths NOLIST directive is

used to lurn oii lisling gen€Elion whilsl lh€ LlsT dir€clive turns it backon

again.

Altematively you can uss the LIST directive wilh eilher plus (+)or minus (-)

as a pararn€l€r to tu rn listing mode on and off. The assembler has an

int€mal lisling slale which slans d 0 and lisling oulpr,.l is only gen€Ialed

when this vaiable is positive. LIST wilhout a paraneler sels lhis variable to

0, NOLISTSetS il to -1, L|STplus incEmenls it and LIST minus decr€m€nls

it.

Example NOLIST islate=-l, no listing

Not listed LIST

Listed LIST

Not listed LIST

Nol listed LISI

LIST

Listsd

Normally lhe assemblerlurns ofl lisling generaiion whenever il is expanding

a macro. l, you need lo see how your macros ars expanding use the /M

switch on ihe command lin€. Similarly code which is being ignorcd dle io

condilional assgrnbly does not go inio the listing unless lh€ /c swiich is used.

i slaie=o, lisiing

- ;slale=-1, no listing

- isiaie='z, no lisling

+ istate=.1, no listing

+ tsiale=o, lisli'rg

Sections and Groups

lntroductlon to Sections and Groups

Seciions are used when you want parls ol your program thal are in dillerent

placss ln lhs source @de lo be placed n€{ to €ach other in memory. ll you

wanl all o, your varjables atthe botlom ol memory lollowed by stfing6

lollow€d by ereculabl€ code then you should be using sections.

Seclions ar€ also used when you want lo produce oulput in a machine

specilic r€localable iomat.

ln addition lo seclions SNASM supporls lhe concopt otgroups which are a

way of making sure c€rlain secllons arc togelh€r in memory and ol

assigning thsm vadous attibut€s.

Syntax

Declaring a gioup :.

GroupName GaOUP lcroup Anributesl

ll a group has mulliple aflnbules th€y ar6 all listed aiterlhe group directiv€

separaied by commas.

Atdhde Funciion

Specily address in memory al whlch to place group

Allows a whole group lo use assembly with otlsei

Speci,ies maximum si:e lor group

BSS groups do not conlain any initialised daia

Tells lhe assembler/linker thal a group can be absolule word

IoFx3

OBJ

stzE

BSS

WORD

FILE Used lo wile contenis o'agroup ro a binary Iie

OVER Causes iwo or more goups lo $an al the sare aod ess in

memory

Opening a seciion :-

SECTION SectionNamel,GroupNamel

ll ihe group name is omitt€dthen ihe seclion willb€ placed in a delauft

unnamsd group unless lhe seclion has been previously assigned lo a

grorp. in whic'r cas6 lhalgroup will be used, lt is possible to wriie a prog.am

lhal doesni use groups at all bd aSS iyoe seciions witt nolbe avaitabte.

The SECIION direclivs can be optionally lollowed by a size specilying its

alignment. The defaull alignmenl is word which means that att parts ot ihe

seciion will slarl on a word bounda"y. ll a seclor s byie atigned ihe EVEN

direciive cannor be used wilhin ii. The CNOP directvo canioi be used to

align lhe PC to a largervalu€ lhan ihe alignmenl ol lh€ curent seciion_

Example u3ing sections and groups

AiB

So lhal vafables can be absolute word addressable ihey must be ai lhe stafi

olthe program. Ths vafiable are lo be lollowed by lwo sections conlaining

slings and one conlaining executable code, Uninitialised data is to rcside

in a seclion of its own above allihe oihers€ctions-

Cede

LowGroup group

Slringcroup group

Codecrcup group

Bsscroup group bss

vaQ

Scratch

Temp

CRLF

Prompl

FaceList

Hello

ors $1000

;When using seclions only one ORG is allowed and it musl be belore

; s€clion de,inilions

section Dala,Lowcroup

dc.w 2

dc.w 89

section Tables,Bsscrol]p

ds.w 256

ds.l 100

seciion.b Slring 1 , Slingc roup

dc.b 13,10,0

dc.b >',0

seclion Tables,Bsscroup

ds.b 64

s€clion.b Sting2,Slingcroup

dc.b 'welcome lo SNASM',o

s€ciion Code,Codecroup

Iea lvrslack,aT

nop

Goups are paced in mernory in lhe order in which lhey arc declared wiih

sections placed within grcsps in the order in which lhey ar€ opened.

PUSHS and POPS

ll you need 10 lemporaily opsn a newseclion (in a macro lor inslancs), you

can use PUSHS lo save ihe current seclion, open a new secr on, and rhel

use POPS to reved lo the old sedbn

Example

i macro lo place lhe cunenl Pc into a separale section

Temp local Temp

pushs

seclion Marksection

clc.l Teinp

pops

eadm

SECkIIIIEESEI

Th€ SECT lunction rslums the bsss ol th€ s€ction In which its F arameter is

dgfined, This cennol be evaluat€d until lhe end ol lh€ second pass it you

arcnl linking, and il you are linking il eannot be €valual€d unlil link iam€.

The OFFSETrunction returnslhs ofls€t olasymbolin its section, which can

always bs €valual€d on the iirst pass. lt you are linking OFFSET relums the

otlssl of the symbol lrom the bas€ ol th€ curent module's contdbution to lhe

sedion, so s€ct(x)+offsel(x) will not equal x. This has be6n done to allow

OFFSET lo b€ evaluat€d at assemble time, which is very ussrullorthings

like :-

n oflse()&1 ; ll curonl PC is odd

dc.b '1 ; add a minus one

6ndil

Note the use ol offsel(') lo gel oltset into s€ction oi clrent PC. ll you want

the rue oflsel inlo s€ction whilsl linking uso x-seciion(x).

Settind Group OAG'S

h is possible lo sei rhe ORG address ol a group totally independani,y ot the

acldresses ol lhe olh€r Eroups.

Exampl€

Code

Data

B9s

Debug

gr0up

group

gioup Bss

ors($80000) ;Debug code 512K

The gmups without lhe org affibut€will be daced sequentatty al lhe acdrsss

given in lh6 oig dksctive as usual,

Ov.rlavlno droubr

ll ls pcsibl€ lo have severalgrouFrs staning atlhe same address using the

OVER attdbule. All of lhe groups will hav€ lhe same start address and

enough rcom willb€ lelt lorthe largest group.

Erampls

Overlayl

OJetlay2

O!erlay3

group

group ove(Ovedayl)

ov6(Oveiay2)

Wrflno GrouE io Flleg

It is possible lo wfle grcups lo seperat€ purc binary liles whilst l€avjng the

other groups to be wdtt€n to ih€ nomal oulpul- This facility is us€d lor

overlay riles and loadeble data liles.

Examplo

Cod€ group

Dala group

Ovgrlayl

Ovedayl b

Owday2

g roup org ($80000),iil€('Oveday 1 .bin')

group ;This also goes inlo ovedayl.bin

g roup orgl$80000),Jils('Ov€ilay2.bin')

Nol€ that all groups declared aller a group thal has a lile atl bule are also

writlen to lhis lil€.

The FILE ett bde can b€ used in conjunction wilh the OVER attribute lo pul

ov€rleys into s€p€rata liles with the start addresses of the overlays att being

Mrchlne Sbeclflc nelocetable Formars

Ifyou are using lhe liflkerto produce.TOS, .PRG or.TTP liles you should

dgclare the following groups.

Text group

Dala group

Bss group bss

Th€ order is not imponad aslhe llnker declarcs ihem implicilly.

llyou do not need to have multipls ssc.tions wilhin each group you can omit

lhe group dedaE ons and us€ lhe delaull group names lo identily the

Example seclion Text

move.w *234.d0

ssciion Dala

dc-w 99

ll yo do lhis you looselhe abilityto have mulliplg sections in each group and

the link€r has lo perlorm lhe ch€cls Jorinitialis€d data in BSS grcups.

A.ulcr

Ityou are using the linker to p,oduce an Amiga executable frle you should

declar€ the lollowing groups.

Code

Data

Bsa

Code_i

Daia_,

B,qg_,

Cod€_c

Data_c

grcup

group

9roup

group

bss

Bss c group bss

The order is not important eslhe linkerdeclares ihem implicitly.

lJ you do not nssd to hav€ multipl€ sections within each group you can omit

the group dedaralions and us€ the detault group names 1o identi, ihe

Example seclion Code

trap #0

seclion Dala-c

Spriteo dc.w 34

l, yo do this you loos€ the abilitylo have mulliple seciions in eacn group and

the linker has to p€dorm th€ checks lorinitialised data in BSS groups.

Linking

SNLINK is a lully i€alured link€rwhich allows you lo writo your pogram in

s€v€rals€parate modules and then linklh€ss modulss together to produce

the final program.

Command lln. svntrr

SNLINK /swilches source(s),outpulrile,symbollile,maplile,libra os

Debug mod€ - do not run

Equate syrhbol

Un onsrnal symbols lo map lile

Set org addr€ss

Asklarcel lor memory lor org address

Produce pure binary oulpul

Produce machine speofic relocatable lile

Set exgcute address

Switches /d

/e symb=value

/o Numb€r

/o ?Number

/r Fomat

/x Number

Relocatable lormats arecurenlly STfor.TOS liles orAM forAmiga hunk

SourcaFlla On€ or more source files (produced by lhe assembler)

separal€d by eitherspeces or plus signs {+) or th6 name ol a

link€r command lile oreceded by an at sign (@)

Oulpulrll. Fil€ b recsive objeci code o"'lpul. llthis is omtied ro objecl

code willbe generated, lJ you want lhe object code lo b€ sent

to a targel compuier use T?: as the obj€cllil€ where ? is rhe

SCS|device numb€r ol lne taroel.

Symbolfll. Frle io r€ceive symbol labls inf;maiion tor debugge'.

M.pFlle File 1o receive map inlormation

Llbrarles Ubrary lileslo search

Linker command llles

Linker command files conla'n instruclions lhat tslt ih€ linkerwhich objecr

lil€s lo rcad, where lo orglh€m and inlohalion about groups, Thes€

inslructions have a v€ry similarfomallo lhe instruclions in the assembter tor

Th€ lollowing instructions can be used:-

j Comment include Filename ; rcad objoct tite

inclib Filename : search tibrary tite

org AddI : OBG address ol prcgram

org ?sizel,lypel ;asr ia.get lor m€mory

r€Es pc=addr : sel €xecdion address

group lanibules] i define qroup

seclion namel,groupl ;delin€s€ction

i nove workspace on largel

Groups are plsc€d in memory in rhe oder in which they are dectar€d, it a

group is d€clar€d in lhe prcgram which is not declared in the command tite il

is placed on lhe €nd ofth€ defned groups.

S€clions within each group are placed in memory in lhe order in which they

are specilied, a seciion is Used in the prooram ilhich is noi doctared in lh;

clmmand lil€ it is placed on lhs €nd ofthe defined s€ctions in the

appropriate group.

Paris of a seclion flom difterent source lites are concat€naied in lhe ord€r in

which lh€ source liles are spocilied.

When groups are dsdared in yoursource @de lhere is no need to specily

any atdbules olh€rlhan WORD and BSS; att other aflributes are ign6red

wh6n linking. lf these affbutes are sp€ilied in the source they muat also b€

specitied rn lhe linker command lile aid vic€ verca.

Example llnker command file

;Command lile lor Amiga Widget sorler

include lnput.obi

include Softer.obj

include Olnpui.obj

org 1024

regs pc=Progsiarl

Lowcroup group Word

Codecroup qroup

Bsscroup group Bss

section Dalal,Lowcrcup

section Dala2,Lowcroup

seclion Codel,Codocroup

section Code2.Codecroup

seclion Tables.Bsscroup

seclion BuffeB,BssGroup

The groups and soctions witt be in ihe tottowino order :

:Start ol erecutablo at 1024

Lowcroup Dalal

Data2

Codecroup Codel

Code2

Bsscroup Tablss

Burrels

The sam€ group anibutes are allowed as lorlhe GROUP dkeclive in ihe

XDEF. XFEF and PUBLIC

When you arc linking s€v€ral modu es togethor you willwant io relerto

symbols d€l5ned in on€ module in difierent module. To do this you must

declare symbols as €xl€mal in the rnodule in which th€y are dgined using

XDEF, andlhen in th€ module in wlrich th€y ar€ us6d you musi use XREF to

lellthe assemblerlhal th€ symbolis in a dilferenl module. Any expression

ihal conlains an XREFU symbol will nol be tully evalualed by lhe ass€mbl€r

and will, instead, b€ resolved by the linker

You can lelllhe ass€mblsrthat a symbolcan be aocessed using absorLtg

word addressing by specilying lhe wod size on rhe XBEF directive.

Exsmple ol XBEF and XDEF

Source modul€ 1xrcl.w LargeTable

xdsl ABoutine,ANolher

section Codel,Tsxl

lea LargeTabl€,ao

ANOlher molu

Sourcd module 2 xdel LaEeTabl€

xrcl ARoutine,ANoher

ssctjon Tables,Bsscroup

ds.w 100

section Cod€l,Ten

isr ARoutine

isr ANOlher

l, you wanl to d€clare a large numberolsymbols as €xiernalyou can use the

PUBLIC direclive to l€llth6 assgmblerthat alt tunher symbots shoutd

aulomatlcally bo XDEF?.

Example

LargeTable

d0,d0

public

Speed dc.w

Dir€clion dc.w

pubtic

50 ;No need to XDEFthis

100 ; orlhis

Libraries

A objeci module libraiy is a lil€ conteining sev€ral objecl modul€s. Thess

librai€s can b€ searched by lh€ link€r iJ it cannol find a symbol in the object

files. ll the linkerlinds thet lh€ enemal symbolii n€eds is derined in a library

module lhen lhe modul€ will be exlracled and linked wiln the objeci

modules.

SNLIB js a ulilily program lor creallng and mainlaining obj6cl module

libraries.

CaEEelll-lils-gller

SNLIB /swiich librarylile modules

switchos /a ldd modulos to library

/d Delet€ modules lrcm library

/u Update modules in library

fi Extracl modLrles lrom library

/ List modul€s in library

The SCSI Link

lnst llhd lh. soltware

SCS|Unk is install€d eilher rrom rhe command lin6 ortrcm a batch rite

(usually auloexec.bat), and it must bs installed berore any olthe assembtsrs

or dsbuggers can be used.

SYNTAX:

SCSlUnk CardAddrl,D?l[,]?]

The address is whatever acldress you sel using linls 0-7 on the PC cad,

andlh€ numberafierthe D shoutd be lte DMA channelyou ar€ using.

!t you havs lell lhe links as supplied jusl insen:-

SCSlLink 390,D1

l, no oMA channel is sp€cilied hardware DMA will ml be used and unless

you have a last cornpuigr dala llansmission speed will b3 r€ducsd,

Th€ I param€l€r is ussd to give the cad a diflerent SCSI devics numb€r

withoui opening lhe compulerand changing the links; this will nol usually be

necessary.

lnt.rfecE 16 scstLtt{K

The SCSlUnk software is acc€ssed using ini 7dh. AH is us€d to s€lecl the

required funclion as shown below.

AH=o Resel SCSI Bus

R€s€ls alldevic€s on lh€ SCSI bus

ln-

O!'

Eno,s

AH-1 Connect to taroet

Arbilral€s lor us€ o, bus and selecls larget.

tn AL=Target tD

Errols CF set i, €ror, Al=lniliator€rror, AH=Targel enor

AH=2 Send command

Sends lhe commend block to th€ target and pefoms and rclated l/O.

In ES:BX. poinlerto parameter block shown below

Oui

Enors CF ssl il enor, Al=lnitiaior eror, AH=Targ€t €nor

Pa,ameter block: (Allwilh 8086 byle ordering)

Size o, command block Dword

Ot s€t o, command block UIonC

Segmenl ol command block Word

Size ot butler Dword

Ollset ol butter Wod

S€gm€nl ol bufisr Word

Th€ conlenis of lhe command block which ar€ desc b€d late r have most

signilicanl byles and words iirctl

AH=3 Set Tim.Out

Change one ot SCSlUnk's intemaliimeouls lo allow communicalion with

very slow tarcBts.

ln AL=TimeOul Numb€r

BX=New value (55ms licks)

Out

Errors

Number Function Delault

0 Timelo waillorbus 18

1 Tim€ to wait lor new phase 5

2 Max lime 10 sendreceive bloct 18

3 Tim6 to wail lor reselect 180

AH=4 G€t Eror Stdng

Gel text 10 pdnl when an eroris reponed,

ln AL=Errcr number

Oul Es:Bx=pointerio zero lerminaied sling

Enors

AH=s Get A.Hr6ss

Get inlormation aboul current hardwarc conriguraiion.

ln-

Out AL=Dma Channel, AH=lnitialor lD, BX=Card Addr

ErroE

AH=6 P'n Data

Save dala lor lai€r r€irieval. (Stored ln PSP ol SCStLink)

ln CX-By.l€ counl (1,256), ES:BX=Data lo sav€

Out

Errors CF set ll €rror, AL:1 Too muci data

AH=7-Ger-&E

Rslri€ve data stor€d using Funclion 6

ln Cx=8yls counl (1 -256), ES:BX=Butler lo ,ill

Oid

E.rors CF sel il sror, AL=l Too much dala

AH=a Terminat6 *sion

lJ a program has mad€ any use ol thes€ link commands il should issue a

Teminate Session command as il sxils ev€n i, il is exiting due lo a SCSI

enor. This command exisls so lhal any soltware ihai iniercepls inl 7Dh

knows wh€n olher programs hav€ iinished with lh6 link.

AtE9-EaL-Bqt/ert

Whenev€ra program pedoms a GetR€gscommand and the exception ihai

has occur€d is nol ons lhal it spscilicelly handles il should perlom a Poll

Request calllo see il6ny driverthai has chained onlo int 7Dh handles il.

This service exists solhatlhlngs sLrch as resid€nl diskseN€6 can continue

to run €v€n whilsl dsbugg€B and prorilgrs arc running, The resid€nl driver

assu.nes lhal a connect has b€€n perlormed andkieslo leave the largei

Oul AL-Targel lD

AL:-l i, a resident diver handled event

AL=-2 il a residenl ddverexpeiencad a SCSIerrcr

Errors

SCSILINK CommEnd orotocol

The lollowinO is a lisl olthe commands cufi€nlly delined. Nol allol ihese

commands arc c{rrenlly suppoded - the Sendlmpl command lets you check

whal commands the soflwarg at the olhsr end suppons, some o, lhese

commands will only b€ handled by downloadsrs which leav6 lh€ machines

OS r€sidsnl, and lhese downloaders usually support some €xlra commands

lo suppot 1116 handling and muhi-lasking.

l, th€ top bit ol a command byle is set lhe larget will disco.nect

alter execuling the command and repo ng lhe slalus. This means lhe

soflware can suppoi up 1o128 commands.

Commands EUer

0 Noop 2

1 Sendlmpl 2

2 S€ndlD 2

3 SendAddr 2

4 RecvAddr 10

5 FindRam 10

6 FlessN€Ram 10

7 Fr€oRam 10

8 ReBool 2

9 Makesale 2

10 Return 2

32 SsndMem l0

oata Adi!tr

Do nothing except reporl stalus

Send binary array ol valid commands

S€nd rnachins/proc€ssor lD

Send slart and lengih ol link workspace

Change address of link workspace

Find how much memory is lroe

Ask OS lor some memory

Hand memory back to OS

Rebool iarget

Prepare lor Be-send

Relurn to OS

Send a block ol memory

;

33 RecvMem 1

34 VeritMem 1

35 Checksum 1

40 SendRegs 2

41 RecvRegs 2

48 GoPC 2

68 G€loSEr 2

0 Out

0 olrt

0lnln

orl

Roceive a block o, memory

Vedfy a block ol rnemory

Generat€ checkum ol a block o, memory

Send regisler block

Receivs regjster block

lnvoke cod€ at PC wilhoul rslum addr

Get result o, lasl OS funclion

Format ot 2 bvte commends

Bde

ESe

2-5

6-9

Function

Command byte

Modilier (sel to zero al unused)

Foriral ol 10 bvt. command3

Funclion

Modifier (set to zero ir unused)

Lenglh field

Addr€ss li€ld

commands ln deiall

N9!!

Command 0

Modilier 0

Functlon

Does nolhing, However lhis can be used lo discon nect lhe tarcet by seting

lhe lop bii as usual.

Se!.cfD.pI

Command I

Modilier 0

Oata-lra[slered Ofisel terlll

Binary aray ol commands 0 16

Functlon

Targel sends 15 byle binary array indicaling which ol lhe 128 commands it

supporls. The data is bigondian so lh6 firsl byt€ is lor commands 127-120.

_ S.ndlD

Command 2

Modirier 0

- Data Transfered Ojjset Lenoth

Processor lD 0 12

Machine id 1? 12

Functlon

Taeel sends slfing giving proc€ssor and madin€ lD.

S!-o!A!-Cr

Command 3

Modifi€r 0

- Data Transrered OflSel telllh

Start of link memory 0 4

Lenglh ol link memory 4 4

- Funclion

Th€ link soltwere repods lhe address and lengrh of the block ol memory il is

using. lllhe link sofiwars doesnl use any ram rhe lengrh will b€ zerc.

RecvAddr

Command 4

Modifier

- Length

Address New address lor link memory

Data Transfered OlGgf L.nr'ih

- New addross 0 4

Functlon

* Causos link sotlwarc lo relocate ilselr.

E lrlB .E

Command 5

Modilier 0

Length

Address Type ol BAM to reserve fiaqet sp€cific)

Data Translered Ollsrt Lenoth

Ram fr6e 0 4

Funcllon

Asks th€ targ€ts OS th€ size ot ihe largest block ol contiguous memory lhal il

can allocatg.

EeserveBam

Command 6

Modifier o

knglh Amount ol ram to reservs

Address Type ol BAM to r€s€lve OaBet specifc)

- Data Transfered Oll$l te!g$

Memory handle 0 4

Address ot ram 4 4

Functlon

Target machine asks OS for ram and passes back a handls which will be

requir€d to lai€rlrce the memory andlhs base address ofih6 btock o,

memory.

Frr.Fam

Command 7

. Moditi€r 0

Lengih

Address Memory handle

Functlon

Hand m€mory back to OS

BeBoot

command 8

Modilier 0

Fu.cilon

Targ€t machine rebools and gogs lhrough normal bool piocess

UBkeSale

Command 9

Modili€r 0

Functton

Target machines puts the hardware into lh6 sarest conliguralion possible_

This usually involves disabling all DMA and int€rrupis, going out of potted

mode and lrssing any r€servecl ram.

Birlrr!

Command l0

Modirier 0

Funcllon

Target retums to OS

S!!!U!n

Commancl 32

Modifisr 0

Lenglh Size of block in bytss

Addross Address oJ block in taEet

Dat. Tr.nsf.red

Stream of bytes

Taeetsencb a block ol ram to initiator

Es.c.IlileE

Command 33

Modilier 0

Length Size of block in bytes

Address Address oi block in laEet

Data Transfered

Stream ol bytes

Ollset Lerclb

0 lengih given in command

Ollsel Leldn

0 length given in command

Functlon

TaEel receives a block o, ram ,rom initiator

V.rlfvil.m

Command 34

Modifi€r 0

L€ngth Size ol block in byt€s

Address Address ol block in targel

Daia Transterod Oflsel Length

Stream of bytes 0 length given in command

Functlon

Targel receives a block o{ ram lrom initiator bul just checks il

againsl current ravn conlents.

CheckSrm

Command 35

Modili€r 0

Length Siz€ ol block

Address Addr€ss ol block in taeet

Data Transfered OIlSgl tellfb

Additive checksum of bytes 0 4

Funcllon

Talget adds logether allthe bytes in the delined lange and retums the long

word resuh

SendBeds

Command 40

ModiJi€r 0

Dala Translerad Ollsel Lenglh

Functlon

The targel sends ils copy ol ths 68000 registeE to the iniliator.

Regisler block lomat is :-

r€gdo ds.l

regdl ds.l

r€gd2 ds.l

r€gd3 ds.l

regd4 ds.l

regds ds.l

regd6 ds.l

rcgd7

rsga0

regal

rega2

rega3

tega4

regaS

rega6

regssp

regusp

regpc

regsr

reginsl

Br.!.IBrcr

Command 41

Modifer 0

D2te Transfered

Regisl6r block

Funcllon

ds.l

ds-l

ds.b

ds.b 1

ds.l 1

Exc€ption typs (-1 =Sladup,

1=Runnins)

Exceplion lunclion code

Address thai caused eror

lnstruclion lhal caus€d €rror

Data TFnsfere.!

OS 6ffor code

Ollsei Ie-EdI

oa2

Oitrst Lelslh

lnilialorsends nsw r€gjsler block to targel,

C-QEC

Command 48

Modirier 0

Funcllon

Targgt reslores all r€gisier from regisier block and iumps to PC

GelOSErr

Command 68

Modilier 0

Fu.cllon

Betums the enor code lorthe lasl OS iunclion lhe link softwarc

Using SnMake

SnMaks was designed lo allow Snasm and associalsd Cross Producls

soltware tools 10 be used from wilhin lhe Bdel editorwith lhe maximum ol

SnMak€ works on th€ lime honourcd mak€ ulility pfinciplo ot rcading a lile

suppli€d by lhe user in which are deiined the rclalionships belween lhe

targs(s) ihs user wishes to cr€at€ and lhe source liles from which thal iargei

is to be created. The target will b6 said 1o b6 d€pendant upon its so!rce tiles

which ers g€n€dcally known as dependencies. The iile in which thes€

r€lationships are detin€d is known as lhs 'mak€Jile', allhough in discussing

SnMake w€ shallalso refer lo them as'projecl liles as willbecome clearer

lat€r Once SnMake has r€ad this nle itdeterminps which largels hav€

dependanls nhich have been updaled since th€ largel lile was created, and

thus which largels musl be recreaied from their dependanls. SnMake

discoveG how lo recreale lhe targets from rules specifi€d in lhe makellls as

discussed b€low. SnMake has a number ol lealures thal allow ii to work in

clos€ conjunclion with Snasm and olher Crcss Pioducts development tools

bui which m€an il diflers lrom lhe more normal make ulillly synlax !n a

Snl\lake and Brlel

Cross Products have pmduc€d a numb€r ol macros rorthe Bdel edilorto

enhanc€ lh€ envilonm€nt lor th€ Snasm user. Some oi lhose macros

inlerlace ihe editor wilh SnMake and allow the user to invoke lhe utiliiy from

within lh6 €dilor. Nole lhal lhe new macros do away wiih lhe dialog-box

jnledace lo Snasm and any user wishing to use Snasm trom wilhin B €J

using the slandard macros will hav€ lo us6 SnMak€ as described below.

This is nol, howeve( acomplex matler.

The followjng descnplion assumes thatthe BieI macros are being used as

supplied, wilhout any reallocalion ol key-binclings.

The Snasm menu is invokedwithin Briel wilh the AllFg keys. The m€nu ilem

'S€lect Proj€ct File' will bring up a N/indow displaying all lhe liles in the

cunent direclory which have a '-pri' exlension. The tirsi line otthese liles is

displayed ro helplhe user rcmembgr whal luncuon lhey perlorm. Ths islhe

mandalory extension for liles to be used as SnMake makeiiles and will be

refened lo as project,iles in lh6 rcmainderollhis section. Should 8de, be

unabl€ lo find any prciecl tiles in the currenl direciory it will display a

msssage on the status line lo that eflect. SnMake can be invoked lrom the

command lin€ wilh the /p switch set (see below tordelails ol switches and

command line usage) in which case it will altempt lo append a'.pi'

sxl€nsionlo the mak€lile name it isgiven. ln lhis mode it is said to be in

'proiecl mod€'. When invokod rrom Biel SnMake is always;n pojecl mode.

Creallng prolecl llle3

Projecl liles musl cornain a lab€lbeginning in the tirsi cotumn otthe form:

ISnMake]

SnMake willignore any t6xt berore lhis labeland ii il iindslh6 €nd o, fil€

belore encounledng itwjllissue an 6rrcr and erit- Wrlhin Bfiellhis will resu[

in an errcr window appearing . Th€ s€arch lorthis lab€lis not case sensitive.

Once il has discovered this label SnMaks will regard eveMhing tottowing as

valid inpui untilil €ncounlers enolher'f in th. firdcotumn;rlhdend of tii'e.

Two olhervalid lab€ls are cunenty suDpoded: lDebugl end [Evar]. They onty

hava signlflcanc€ il the proj€ct lile is sereded wlhin Bnet. The lext non-

blank llne lollowing lhe lDebug] label is d€€m€d to hold the Debugger

command line the userwishgs to have issued upon invoking the'Debug,

m€nu selection trcm lhe Snasm n6nu ( s€e 'Usang SNASM wilhin Brief ror

details on using th€ new Snasm macros wilhin Bi€l) and simitadyrorthe

line following lh€ lEval] label which invokes th€ exprsssion evatLiator ot the

ussrs choics. ln lhe case ol lhe IEvaI comnand rine 6 sp€cial loken SS$'

can be placed in the sldng and any ma*ed input witr be ptacsd in ihe siing

al lhal poinl.

Thus a simpl€ project lile might look as lollows:

----b€ginning oi iile here------

projed lile lo assemble prog.68klo17:

lsnmakel

17a, prog.68k

snasm6Sk $l prcg.68k,t7:,prog.sym

[D€bus]

snbug6Sk prog.syn

IEvall snbug6Sk to$$$ prcg.sym

DefinlnO targeis.

SnMake r€gards anything srarting ln colurnn 0 and rerminated wilh a.;, as a

targsl d€daration. Thus:

targsll;

tgtl;

eihislgl;

are allvalid laEsl namos. White space ln tarcel dedaralions ls strlppod out.

Deflnlng dependencles.

Anylhing iollowing the ';' on the same line as a taEel decla€llon is regarded

as a dependencl declaralion. Multiple dgpendenciss are declared

separaled by whiie spaca and lin€ cutinualion (see b€low) can bs used.

The lollowing line:

largell.cp€; src1.68k src2.68k

declares that targetl .cp€ is d€p€ndani on src1 .60k and src2.68k and

SnMako will a empl to invok€ any rules defrnsd ,or larg€t1 .cpe il the

dalenime slamps ot €ilh€r srcl .68k or src2.68k snow them lo have been

updaled since targetl .cp€ was lasl cr€at€d,

speclal targets.

SnMake suppons a numberol spsciallarg€ls,

.lNlT; any commands lollowjng lhis target dsclaration will always be

ca ied oul lirsl when thls prcject lile is executecl.

.DONE; any commands tollor dng thls target declaration will always be

carried out lasl when lhis prcloct lil€ is sxecut€d.

-lNlTand.DONE clo not have to be declared aslh€ lirst and last targels

within lhe makeiile, Snmake u/ill recognise th€m and rc-adjusi its lisi of

largels accodingly. .lNlT and .DONE will always be execlJl€d and should

nol be d€clar€d with depsndants.

l?:; the larcels on lhe SCSI bus are recognised and wi,l always

cause th€ rul€s associal€d with il to be invoked. These largels should be

declared wilh d€p€nd€ncies.

l7:: src1.68k

snasm6Sk $l srcl.68k,17:

declares that src1.68k should be asssmbled down to SCSI raeel t7: . This

wiltoccur every time th€ projocl rils is exscuted. See secrion Speclal

Macros'lor th€ significance of'$l'in ihe command,

.RESOUFCE; lhjs larget dedaralion should be lollowed by a lisl

ol programs lhat are able to utilise resource filss, ll musl be the iirst item

declared int lhe prol:ect ,il€ alt€r lhe lsnMakel label.

l, a command line lor one o,lhese prcghms exc€€ds 128 characl€rs in

lenglh, SnMake will splil it down into a temporary lile wiih each command

line aigum€nt plac€d on a now line and will callthe command with that iile

prsceded by an '@' charact€r. i,e.

lSnMak€l

BESOUCE;

lgt; d€p1

somecmd depl .......... very long command line > 128chars

det€cling an overlong command lin€ SnMaks will create a temporary

r€source fi16 and call som€cmd as lollows:

som€cmd @lmpl .$$$

Deflnlng orpllcli ru1e3.

Anything lollowing the end ol e laEel declaElion line is considered a rul€

dedalation. To be valld;a ru16 declaBlion must be ind€nt€d by at leasl one

space or lab. Blank lines lollowing a largel d€claralion arc ignored. More

than one command may tollow a gven largel, each stariing on a new lirc

and indenled as described above-

largell.obj; depl d€p2

snasm6Sk I dopl dep2,targsll .obi

delines a rule lelling snMak€ lhal illargell.objis yo!ngerlhan eitherdepl

or dop2 it should issus lhe comrhand

'snash68k,1 d€pl dsp2,largell.obj'

Deflnlng Impllclt rul$.

ll SnMake cannol rind an explicil rute with which lo create a targ€t il will

atlempt lo do so by invoking any implicit rules delined in the prcjecl lile.

lmplicil rul€ delnnions musl begin in lhe flsl column and begin wilh a'.'

character SnMak€, on s€arching the list of implicii rules il has delined, looks

lor a rul€ that matches ihe exlension of lhe larget il is lrying 1o mak6. This is

the firsl portion of the implicil rule declaralion. Thuslo delin€ an implicii rule

thal SnMak€ will use lo d6al wilh any targets wilh a '.obj' €xtension rhe

lollowing is the required li6l pan or lhe dedararion:

.obj

having found liis SnMake will proce€d to atlsmpt lo fiatch lhe second pan

ol the declaralion; ihis is delimhed irom lhe ftrst part by a ',' characler thus:

.obj,.68k

this inloms SnMake thal any largets wilh a '.obj' extension are to be created

lrcm a depsndsncy oflh€ sam€ name but wilh a'.68k exlension. Th6

second part olthe declaralion fiusl bogin wilh a'.'characl€r, unlsss a path

nams is speciied as below:

.obi,e1€mp\.68k

This tells SnMak€ that any ta€els rvilh a '.obj' €xlension are lo be crealed

lrom a dep€nd€ncy oflhe same name bd wilh a'.68k extension in directory

e:lemP.

Dellnlng .ul€s tor lmpllcll iarg6t3.

The rule iollowing an lmpllcil target dorinition must be indenlsd by al least

one space or tab.

Two macrcs exist lo aid sp€cjlying implicil rul€s. These are $+ and $-. $+

signilieslh€ largel and $- its depndency. Thuslhe following impliol rule

.obj,.68k

snasm6Sk $+,$-

wh€n invoked upon target progl.obj will resull in ihe following command:

snasn$8k progl .68k,prog 1.ob,

Points io note on using implicd rul€s.

a. Explicil ruleswillalways be used in prelerence lo implicit rules i,

explicil rules have been sel lor a givefl largel.

b. ll mor€ than on€ set ol implicil rules are delinecl lorthe same target

group,lhal implicil rule mosl rec€ntly d€lined (in lerms of position wirhin ihe

project lile)willbe invoked upon any suitabletaqels thus:

.obj,.68k

any suitableiargels in lhis areawillb€ cr€at€d irom files ofthe same

name with a "68k €xt€nsion,

.obj,el€mp\.68k

iollowing rhis new implicil rule delinition any suitabl€ targ€ts in lhis

arsawillbe crealed from liles ollhe same name wilh a '.68k' exiension in

dkectory e:lemp.

Macios.

Macros can be passed into SnMake lrom the command line using the /e

sr rilch as d€scrib€d below in the Command Line Options section. Within a

make/proiecllile the can b€ delined using the lollowing synlax:

maCiOl=SOm€nam€

macro dejinitions must begin inlhe fltsl column ollhe line. White space is

- sldpp€d oul ol macro derinitions.

Wh€n delin€d macros ar€ rergrencgd they must be idenlified using the

,ollowing melhod :

$(macroname)

thus giv6n lh6 abov6 macro d€linition $(macrol ) will €rpand to lomenam€',

'$'signs can b6 prot€cled lrom att€mpl6d macro expansion by the addition

_ ol the macrc syntax brcak€r'$. Thus $$20000 is passed though SnMake as

$20000.

_ The lollowing macro funclions allow th€ us€rto manipulat€ definod macrcs.

$e(macroflame) €xpands lo lhe extension oi macrcname,

maCrcnAme=t6st.Obj

-- $e(macroname) sxpands ro'.obj'

$n(macroname) expands lo onlylhe rilenams oflh€ macro dslinilion

macroname=6lesht€st.obj

- $€(macronam€) expands 1o t€st.obl

$p(macronam€) €xpands lo the palhnam€ ofthe macrc delinilion

macroname=6lesl\lemp\lssl,obj

$p(macroname) expands lo el€st\t€mp\'

_ $d(macroname) expands tolhs d vs nam€ oflhe macro delinition

macrcnam€=e16sl\lemp\len.obj

$d(macroname) expands to'e:'

'- $b(macroname) expands lo the lilename in th€ macro delinition

macroname=€ lesl\lemp\prog 1 .obj

$b(mecroneme) expands to'prog1'

Line contlnuetlon.

- To conlinu€ a line without introducing a n€w1in€ character the 1'character

lollgdialejy loliowed by a carriage return is used. Thus

lhistgl; d€pl d€p2 dep3 d€p4 deps dep6 depT depS depg \

- dep10 depl1

declares depl lo dgp11 as dep€ndencies io rhisrgr. Wlhoul lle conriuai'on

maft SnMake would lruncale fte d€psndency lisr at depg.

Commsnts.

A line on which lhe filst characl€r is a hash ma* will be regaded as a

Speclal macro3.

For use wilh Snasm and Snlink a spscial mac.o is provided by SnMake

which allows lh€ s9tting o,lhe I and /d switches on lhe command lines of

those programs.

The/i switch lo Snasm and Snlink lorces them to create an outpuwindow to

which they send lheiroulput whilsl running. This €nabl€s the user to watch

th€ir progress ,rom wirhin B.iei. This oplion is always s€l by the Bdsl macros

supplied by Cross Produc'ts.

The /d swilch to Snasm and Snlink lorceslhem inlo debug mode, ii aJile is

being assembled,'linked lo alarget machine il willnol be run ifthis switci is

set;thus allowing th€ us€rlo €nt€r the debugger belore execution of thal

csde starts. This option can be coniroll€d lrom lhe Bdel Snasm m€nu using

lhe 'Set Debug Mode' menu iism,

Conlrol of these switch€s is not possible lrom wilhin Bfel il the $l macro is

nol presenl on the Snasm6Sk and Sniinkcommand lin€s in lhe project lile

largl; depl dep2

snasmoSk S! / d€pl dsp2,taEl

assuming lhat debug mode is set lo 'ON! using ihe 'Set Debug Nlod€' oplion

Itom Bieflhis command willexpand io

snasmoSk I /d I depl dep2 ,l,arg1

ln addilion lhs /d and ,,i swilchss sel up lwo macros, D€buqstr and lnlosr,

which can b€ t€st€d with the lilde, command as descdb€d betow.

Condlllonals.

A conditional capability is prcvjd€d within SnMake by the lildef command.

This allows the user lo delermine ila macro is derin€d and act upon that

inlonnation. Thus in lhe lollowng case:

l7:t prog1.68k

snasmoSk $! prog1.68k,t7:,prog1.sym

liJdsl(D€bugstr)

snbug6Sk prcg1.sym

il ihe special macro 'oebugsti is s€l i e. debug mode is on, the debugger

willb€ invoked every lime SnMak€ is 'Noked with lh's proteci lite.

The l€ndilclmmand is rcquired lo l€lminale lh6 lildel call. Il SnMake

reaches lie end of th€ projscl lil€ with an unbalanced numb€r o, calls to

liidel and lendif an erorwillr€sult.

An lelse stalemenl is also supporled as shown below:

!idsl(Debugstr)

t7:; progl.68k

snasm6Sk $l prc91 .68k,17:,prog 1.sym

snbug6Sk progl.sym

17:; prog1.68k

snasm6Sk prcg1.68k,r7:

This example perlorns lhe same task as the previous one in asliglrtly more

rou.d-aboul manner.

lnvoklng Snlttako from th6 command llno

Th6 syntax lor calling SnMake lrom lhe command line is aslollows:

snmake <swirches> <makeile> <enor,ile>

all arguments on the command line are oplional. lnvoking SnMake wnh no

argum€nls callrses it lo look lora makeiile called 'makefile' and process thal.

The opiional <make{ile> parameler specilies an alternalive makelile name. lf

<errorfile> is speci,i€d all€rroi inrormalion will be oulpul to lhal lile.

Switchss :

SnMake ac.epis live swilches lrom the command line.

/q Oui€t mod€. No echoing is done as SnMak€ prcceeds.

/p Proj€ct mode. This lorces SnMake lo treal mak€liles as prcjecl liles

i.e. as il invoked lrom within Bnef. ll no makerile name is specili€d

SnMake will detaull lo maketile.pi. ln project mode all oulput from

SnMake goes io a file call€d snmk.€r, any ermroulpul lromlhe

programs invoked by Snlvlak€ will appear on-sceen unless an error

Jile is specilied.

/d Set debug mod6. S€ls the specjal macro $1. Only ol use i, invoking

snasm or snlink lrom ihe makelile,

,,i S6t into mode, As above.

/9 Pass a macro delinilion lnto SnMake. Synlax /enam€=Frcd.

This would sel up a macro name which would expandlo Fred.

,D Build all. All rules carried oul regadless .

Exampl6s:

The lollowing example is a projecl liles lhat will prcduce a Jile called

lesll .cpe lrom ih€ sourcs liles e |srcl .68k e:src2.68k . Iert in this style is

cofifient text a&ecl to aid the reader and is not pan ol he SnMake syntax.

-------------Ptuier,

,ile io create tssrl.cpe fhis on will appeat in the projec! file

tSnMakel Snnake in pmject nade stais rcading at

this label

srcl.obt; esrc1.68k

5nasm68k $l I /z e:src1.68Lslc1.obi,src1.sym

src2.obj e:src2.68k

snasm6Sk $l / /z €:src2.60k,src2-obi,src2-sym

lesll.cps srcl.obj src2.obj

snlink $! src1 .obj src2.obi, lesll .cpe

lD€bugl SnMake stops rcacling herc-

Snbug68k src1.sym src2.sym Debugget is invoked using this

sfing

lEvall Snbug6Sk V$$$ srcl.sym src2.sym Exptessbn evaluatot is

invoked with this shng

-------End ol project frle--------

Other Utilities

Sncopy

Tl'rs uiihy is a vadanr on ihe copy command in lhal ii wilt ontv @ov thosa

source fles ihat have been more r€cenity wdfl€n ihan anyta;letiries il tinos

ol lhe same name

li haslhe tollowing command tine syntax:

sncopy <swilches> source1+source2+.... la€et direclory

wh€re swilches arel

/a - r€lr6sh atti rsg-sdtess oJ retative ages (retresh AI rhode).

/q - do nol echo afier retresh (Outet hode).

sncopy f le1.68k+tit€2.68k c:\source

would caus€ sncopy lo ssarch in d,reclory c:\sourcs tor tites named

Illel.68k and lile2.68k and compare therr tim€ and dale stamps (iiihe

files exisl)lo those ollhsliles ot the sans name in the currerit

drrectrcry. tflhe tit€s in th€ current directory are newerltlan those in

c:\source orfites onhe same name do not exrst in c:\60urce a copy wifl

ln the lottowing case, due lo the uss ot ihe /q and /a swiiches alt tites

are copied and no echoing is done to lhs screen.

sncopy /q/a ,ite 1.68k+rite2.68k c:hourc€

Sncopy supports wildcard paflerns:

sncopy '.68k d:\src

will copy att fl€ ending in the ,.68k enension tflo lhe drrectorv d.\src i,

no younger lile ot lhs same name is tound resioing lhere. '

Slcopy will be of mosl use lo those who keep copies ot source liles on a

rast d€vice, such as a ram dtst(, whitst lhey wdrk o'n rhem and wil thus

oenem Dy usrng a copy program ihal wil nol alow the accidental coovind ot

or0 source lites over thos€ ihsl have b€€n more recen y updaied. ' ' -

lndex

\$ 50

\'49

\@ 51

-RS 27

_DAY 28

.HOURS 28

_MINUTES 28

_MONTH 28

_SECONOS 28

_WEEKDAY 28

YEAR 28

ALIAS 22

CASE 41

cNoP 33

DATA 31

DATASIZE 3I

DC 30

DCB 30

DEF36

OISABLE 22

DO 43

os 32

ELSE 39

ELSEIF 39

ENO 39

ENOCASE 41

ENDIF39

ENDM 44

ENDB 42

ENOW 42

EOU 24

EOUR 28

EOUS 25

EVEN 33

FAIL6l

FILESIZE 36

HEX 31

lF 39

lNcBtN 35

INCLUDE 35

INFOBM6l

INSTR 53

LtsT 62

LOCAL 57

MACRO 44

MACROS 46

MEXIT 44

MODEND 55

MODULE 55

NARG 45

NOLTST 62

OBJ 34

OB.JEND 34

OFFSET 65

OPT 58

ORG 33

POPO 60

POPP 50

POPS 64

PUBLIC 70

PUBGE 51

PUSHO 60

PUSHP 50

PUSHS 64

BADIX 20

REF36

REG 29

REGS 38

aEPr 42

RS 27

BSBESET2T

RSSET 27

sEcT 65

SET 24

SHIFT 45

STRCMP 53

SIRLEN 53

SUBSTR 54

TYPE 36

UNTIL43

WHILE 42

WORKSPACE 38

XDEFTO

XREFTO

mo,.rozJa<c r

SNASM68K 68000 Cross Assembler System Manual

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