Nintendo DMG-01 Manual - Page 7

Game Boy, CPU Manual, by DP

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Game BoyTM CPU Manual 2.4. Processor have been added and some have been taken away. The following are added instructions: ADD SP,nn LDI (HL),A LDD (HL),A LDI A,(HL) LDD A,(HL) LD A,($FF00+nn) LD A,($FF00+C) LD ($FF00+nn),A LD ($FF00+C),A LD (nnnn),SP LD HL,SP+nn STOP SWAP r ;nn = signed byte ;Write A to (HL) and increment HL ;Write A to (HL) and decrement HL ;Write (HL) to A and increment HL ;Write (HL) to A and decrement HL ;nn = signed byte ;Stop processor & screen until button press ;Swap high & low nibbles of r The following instructions have been removed: Any command that uses the IX or IY registers. All IN/OUT instructions. All exchange instructions. All commands prefixed by ED (except remapped RETI). All conditional jumps/calls/rets on parity/overflow and sign flag. The following instructions have different opcodes: LD A,[nnnn] LD [nnnn],A RETI by DP Page 7

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Game Boy
TM
CPU Manual
2.4. Processor
have been added and some have been taken away.
The following are added instructions:
ADD
SP,nn
;nn = signed byte
LDI
(HL),A
;Write A to (HL) and increment HL
LDD
(HL),A
;Write A to (HL) and decrement HL
LDI
A,(HL)
;Write (HL) to A and increment HL
LDD
A,(HL)
;Write (HL) to A and decrement HL
LD
A,($FF00+nn)
LD
A,($FF00+C)
LD
($FF00+nn),A
LD
($FF00+C),A
LD
(nnnn),SP
LD
HL,SP+nn
;nn = signed byte
STOP
;Stop processor & screen until
button press
SWAP r
;Swap high & low nibbles of r
The following instructions have been removed:
Any command that uses the IX or IY registers.
All IN/OUT instructions.
All exchange instructions.
All commands prefixed by ED (except remapped RETI).
All conditional jumps/calls/rets on parity/overflow
and sign flag.
The following instructions have different opcodes:
LD
A,[nnnn]
LD
[nnnn],A
RETI
by DP
Page 7