6502_Instruction_Set_Summary 6502 Instruction Set Summary

User Manual: 6502_Instruction_Set_Summary

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~

MOS

TECHNOLOGY,

INC.

Valley

Forge

Corporate

Center

950

Rittenhouse

Road

Norristown,

Pa.

19401

MCS6500

SET

INS

T'R

U C T

ION

SUMMARY

PROCESSOR PROGRAMMING

MODEL

i

PCH

PCL

j

,

INlvl

Ie

101'

Izici

~

ACCUMULATOR

INDEX REGISTER

INDEX

REGISTER

PROGRAM COUNTER

"PC"

STACK

POINTER

"S"

PROCESSOR

STATUS

REG

"P"

CARRY

1 =

TRUE

ZERO 1

'"

RESULT ZERO

IRQ DISABLE 1

'"

DISABLE

DECIMAL MODE 1

'"

TRUE

BRKCOMMANO

OVERFLOW 1 z TRUE

NEGATIVE 1 = NEG.

INSTRUCTIONS

I"UDI"'T£

AISOlUT£

lERO

~AGE

ACCUM

IMPLIED (lNO.X) (lND).Y

i.PAGE.x

AIS. X

...

as.

V RElATIVE IliIDlRtCT

i!.~"'GE.

V

CONDITION

CODES

_EMOIIIC

OPERATION

OP N #

OP

N #

OP

N

_ OP

NI_

OP

N #

OP'

N -

OP

N

1#

OP

N #

OP

N -

OP

N #

OP

N #

OP

N -

OP

N # N , e , D V

ADC

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BRANCH

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ON

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ON

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IMMEDIATE AISOlUTE

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(lND)O

(lNo),

Y

i!.~"'GE,X

US,

X

...

IS

.... IIiDIREeT

~PAGE.'"

CONDITION

COOES

111010111:

O'fRATIOI

OP

N

#OPN

#

OPN

#

0..,

#

OPN

#

OP'"

#

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#

OPN

#

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#

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#

OPN

#

OP

...

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N

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.... x

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6 1

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s

....

x

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x-s

TVA

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3

las

3 ,

IF PAGE BOUNDRY

IS

CROSSED

ADD 1 TO

"N"

IF 6RANCH OCCURS

TO

SAME PAGE

ADO 2

TO

'N"

IF 6RANCH OCCURS TO

DIFFERENT

PAGE

I"

I'

,

F8 2 I

AAI2

1

9A

2 I

'"

, ,

X

INDEX,

x

A

ACCUMULATOR

I

81

6 I 2

"'1,1,

I

-SUBTRACT

99 ; 3

..

EXCLUSIVE

OR

MODIFIED

NOT

MODIFIED

, ,

N

NO.

CYCLeS

.,

NO.

BYTES

-

..

IF IN DECIMAL MODE Z FLAG

IS

INVAliD

ACCUMUlATOR

MUST

BE

CHECI<ED FOR ZERO RESULT. M

MEMORY

PER

EFFEcrlVE

ADDRESS

M5

MEMORY

PER STACK POINTER

M,

MEMORY

81T

7

'.16

MEMORY

81T 6

QP

-CODE

TABLE

~

MID

•

,

•

6

8

ORA

IND, X

ORA

2.

Pago

ANO·INO,X

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EOR

2

Page

lSR

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ACC

IND. X

ADC

~

Page

STA

INO, X

STY

~

Page

STA1!

Page

STX·2-

P;oge

lOA·INO,

X

,CD"P'~

LOA

2!

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Page

CMP

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l

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CPX

2-

.~.ge

SBC.i!

Pa.~,

INC

2-;f~~

IMMEDIATE

ADDRESSING

-

THE

OPERAND

IS

CONTAINED

IN

THE

SECOND

BYTE

OF

THE

INSTRUCTION

ABS·

ABSOLUTE

ADDRESSING

-THE SECOND

BYTE

OF

THE

INSTRUCTION

CONTAINS

THE

8 LOW

ORDER

BITSOF

THE

EFFECTIVE

ADDRESS

THE

THIRD

BYTE

CONTAINS

THE

8

HIGH

ORDER

BITS

OF

THE

EFFECTIVE

ADDRESS

l PAGE

ZERO

PAGE

ADDRESSING

SECOND

BYTE

CONTAINS

THE

8 LOW

ORDER

BITS

OF

THE

EFFECTIVE

ADDRESS

THE

8

HIGH

ORDER

BITS

ARE

ZERO

ACCUMULATOR

ONE

BYTE

INSTRUCTION

OPERATING

ON THE

ACCUMULATOR

l PAGE.X

~

PAGE Y

ZERO

PAGE

INDEXED

THE SECOND

BYTE

OF THE

INSTRUCTION

IS

ADDED

TO

THE

INDEX

(CARRY

IS

DROPPEDI TO

FORM

THE LOW

ORDER

BYTE

OF

THE

EA

T,iE

HIGH

ORDER

BYTE

OF

THE

EA

IS ZE

ROS

A

PL~

i

"Of""

D

LSD/

//MSD

ABS x ABS Y

ABSOLUTE

INDEXED

THE

EFFECTIVE

ADDRESS

IS

FORMED

BY

AODING

THE

INDEX

TO

THE

SECOND

AND

THIRD

BYTE

OF

THE

INSTRUCTION

liND

X~

INDEXED

INDIRECT

THE

SECOND

BYTE

OF

THE

INSTRUCTION

IS

ADDED

TO

THE

X

INDEX,

DISCARDING

THE

CARRY

THE RESULTS POINTS

TO

A

LOCATION

ON

PAGE

ZERO

WHICH

CONTAINS

THE 8 LOW

ORDER

BITS

OF

THE

EA

THE

NEXT

8YTE

CONTAINS

THE B

HIGH

ORDER

BITS

(lND~.Y

INDIRECT

INDEXED

-THE SECOND

BYTE

OF

fHE

INSTRUCTION

POINTS

TO A LOCA

-

TION

IN

PAGE

ZE-RQ-

THE

CONTE~TS

OF THIS

\~E"'10RY

LOCATION

IS

ADDED

TO THE

'0'

INDEX

THE RESUL T

BEING

THE LOW

ORDER

EIGHT

BITS

OF THE

EA

THE

CARRY

FROM

THIS

OPERATION

IS

ADDED

TO THE CONTE!\JTS

OF

THE IIJEXT PAGE

ZERO

LOCATION

THE

RESULT

BEI'lJG THE 8

HIGH

ORDER

BITS

OF

THE

EA

pc-

. ,

. ,

" 4 I 6

L--f-f--II

4

\1

7

RTI

F F F A

AOL

F F

AD

H

F F F C

ADL

F F F 0

ADH

F F F e

AOL

05

F F F

FAD

H

114

_.

~SP

AFTER IAQ

OR

NMI

BUT BEFORE

ATI

BEFORE

I RO OR

NMI

AND AFTER RTI

_PCATTIMEORIRQOR

NMI • THIS INSTRUCTION

WI

LL

COMPLETE

BEFORE

I I

AVICEO

INTERRUPT SERVICE

MAIN

BODY

RETURN FROM

INTERRUPT

NMI VECTOR

RES

VECTOR

lAO

VECTOR

FIG.1

IRa.

NMI. ATI, BRK OPERATION

pc-

• 3 • • J 5 R "

• 3 • 1 A 0 L

.,

0 3 , , A 0 H

..

, 3 • 3

" 4 " 5

, 4 e 6

II

4 e 7

114118

RTS

"

FIG.:Z

JSR,

RTS

OPERATION

JUMP

TO

SUBROUTINE

RETURN FROM SUBROUTINE

TO

THIS LOCATION

SUBROUTINE MAIN

BODY

RETURN FROM SUBROUTINE

ASCII CHARACTER SET (7-BIT

CODE)

ASSEMBLER DIRECTIVES

~

• , 2 , • 5 6 7

•

OPT·

IF

useD

MUST

BE

THE

FIRST

EXECUTABLE

STATEMENT

IN THE PROGRAM. LSD

...

."

."

" ,

,,,

,.

, ,

10

, "

• OPTIONS

ARE:·

IOPTIONS

USTED

ARE THE

DEFAULT

VALUE.

TURNED

OFF

BY

(NO) PREFIX.)

COUNT (COU

OR

CNT)·

LIST

ALL

INSTRUCTIONS

AND

THEIR

USAGE. ,

0000

NUL

OLE

SP

, • p P

NOGENERATE (NOG) -DO NOT GENERATE MORE

THAN

ONE LINE OF CODE FOR ASCII STRINGS. ,

01)(111

SOH

DC'

I 1 A Q q

XREf

(XflE)·

PRODUCE A CROSS-REFERENCE LIST IN THE SYMBOL

TABLE.

2

0010

STX

DC2

2 B R b

ERRORS

(ERR)·

CREATE

AN

ERROR

FILE.

MEMORY

(MEM) . CREATE

AN

ASSEMBLER OBJECT OUTPUT

FILE.

,

0011

ETX

DC'

# , C S

LIST

(LIS)·

PRODUCE A

FULL

ASSEMBLY LISTING. •

011010

EDT

DC.

S 4 0 T d .

•

BYTE·

PRODUCES A SINGLE

BYTE

IN

MEMORY

EQUAL

TO EACH OPERAND SPECIFIED.

•

WORD·

PRODUCES TWO BYTES IN MEMORY

eQUAL

TO

EACH OPERAND SPECIFIED. 5

0101

ENG

NAK

% 5 E U "

-

...

DEFINES THE BEGINNING OF A NEW PROGRAM COUNTER SEaUENCE. 6

01

HI ACK SYN • 6 F V f

• PAGE -ADVANCES THE LISTING TO THE TOP OF A NEW PAGE. 7

0111

BEL

ETB

7 G W , w

• END -DEFINES

THE

END OF A SOURCE PROGRAM. B 11100

BS

CAN I B H X h ,

9 11101 HT

EM

I 9 I Y ; y

A

1010

LF SUB J Z j ,

B

10'1

VT

ESC

, K [ k

LABELS: C

1199

FF

FS

< L \ I I

LABELS

BEGIN

IN

COLUMN 1

AND

ARE SEPARATED FROM THE INSTRUCTION

BY

AT

LEAST

ONE SPACE. 0 11111

CR

GS

-M ] m

LABELS

CAN

BE

UP

TO

6

ALPHANUMENIC

CHARACTERS LONG

AND

MUST BEGIN WITH AN

ALPHA

CHARACTER.

A,

X,

Y,

S,

AND

P ARE RESERVED

AND

CANNOT

BE

USED

AS

LABELS. E

1119

SO

RS

. > N t

~

LABEL

-EXPRESSION

CAN

BE

USED

TO

EQUATE LABELS TO INSTRUCTIONS. F

1111

51

VS I , 0 -p DEL

*-*+

LABEL

N CAN

BE

USED

TO

RESERVE AREAS IN MEMORY

CHARACTERS USED

AS

SPECIAL PREFIXES:

INDICATES AN ASSEMBLER

01

RECTIVE

# SPECIFIES THE

IMMEDIATE

MODE OF ADDRESSING.

SPECIFIES A

HEXADECIMAL

CHARACTER.

" SPECIFIES

AN

OCTAL

NUMBER.

'J(,

SPECIFIES A

BINARY

NUMBER.

SPECIFIES

AN

ASCII

LITERAL

CHARACTER.

()

INDICATES

INDIRECT

ADDRESSING.

IN

COLUMN 1 INDICATES A COMMENT.