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gianlucag / mos6502

A fast & simple MOS 6502 CPU emulator written in C++
MIT License
288 stars 56 forks source link

Misleading README suggests that Commodore 64 used, 6502. #21

Closed kaitabuchi314 closed 1 month ago

kaitabuchi314 commented 1 year ago

The README suggests the C64 used the 6502, but actually, it used the 6510, is this a 6502 emulation or 6510? It suggests you could make a C64 with this emulation, but if it is a 6502 emulator, it may or may not work.

gianlucag commented 1 year ago

The 6510 is essentially a 6502 with some built-in hacks to make it work on a C64. It can disconnect itself from the address/data buses by three-stating the address/data pins and it's got additional output pins to bank switch the ROM chips. Instruction set wise is fully compatible. This is a 6502 emulator, so yes, not a 6510 emulator.

kaitabuchi314 commented 1 year ago

Can this be used to make a C64 emulator/simulator/what ever you call that? If not, the Commodore 64 part should probably be removed. This is because someone may think that they can!

gianlucag commented 8 months ago

Can this be used to make a C64 emulator/simulator/what ever you call that? If not, the Commodore 64 part should probably be removed. This is because someone may think that they can!

It can be totally used to make a C64 emulator. Three-state pins and the extra 6 bit I/O port would be coded outside the cpu emulator itself. The three state thing is a synchronization problem, while the 6 bit I/O port is encoded in the address decoding login of the emulator.