Questions tagged [z80]

The Zilog Z80 microprocessor. Prefer [game-boy] instead for questions about the Game Boy CPU nicknamed the ‘GBZ80’.

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5answers
6k views

Why did Pokémon Red have so many overflow bugs?

(This question also applies to other Game Boy games, but Pokémon seems to be one of the best-documented.) Pokémon Red & Blue (Red & Green in Japan) is a pair of Game Boy games about capturing &...
45
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2answers
12k views

How did the Z80 instruction set differ from the 8080?

The Zilog Z80 microprocessor, known for its use in the ZX Spectrum, was designed to be a backwards-compatible extension to the Intel 8080 processor. It introduced several new instructions to the 8080'...
24
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4answers
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Use of undocumented opcodes

I figure this is fitting for Retrocomputing.SE because CPUs like the 6502 and Z80 and the PDP-8, and probably others, have undocumented instructions and will happily execute them, in contrast with ...
34
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2answers
2k views

Can the two CPUs in a Commodore 128 run at the same time?

The Commodore 128 has two CPUs. One is some variant of the 6502, and the other is a Z80. One CPU is there for compatibility with the Commodore 64 and the other is there presumably to give basic ...
11
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2answers
1k views

Faulty M1 line on the Z80A

It is well known that some Z80A processors with non functioning M1 signals were assembled into many ZX Spectrums. As this signal is not used in the main board and not everyone bought interfaces that ...
13
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5answers
5k views

Looking for a Z80 simulator/emulator for Linux

I've seen simulators for the 8085 (i.e., sim8085) but not the Zilog Z80. Is there a similar sort of editor/assembler/compiler/debugger simulator for the Z80?
24
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5answers
2k views

How much benefit should be expected on a more advanced compiler for z80/r800 based computers?

I am self studying about compilers, and get hands on very good textbooks about the subject. I am thinking in develop a compiler using the almighty llvm infrastructure to cross compile to old computers,...

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