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
EX DE,HL や EX HL,(SP) は8080からあるが、それも削ったみたい。 ゲームボーイ専用ではないかと。ポケコン以下なので流用先もなさそう。
ゲームボーイはZ80だったのか… (スコア:1)
6502だと勝手に思いこんでたよ。
ファミコンからの移植大変だったんじゃないのかなあ
Re: (スコア:0)
Z80というより8080に近かったようですが
液晶と抱合せでシャープのIP使ったのでしょうね
Re:ゲームボーイはZ80だったのか… (スコア:2, 参考になる)
Z80比
http://marc.rawer.de/Gameboy/Docs/GBCPUman.pdf [rawer.de]
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
EX DE,HL や EX HL,(SP) は8080からあるが、それも削ったみたい。
ゲームボーイ専用ではないかと。ポケコン以下なので流用先もなさそう。