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"D" == Dunny <paul.dunn4@ntlworld.com> writes:
D> What's the compatibility like for the z80 side of things? Meaning D> the undocumented opcodes and flag behaviour?
Yes and Yes. The Risc can run Z80-Software with undocumented Opcodes. Its full softwarecompatible but not cycle exact. The 6502-Software runs only with documented 6502 opcodes and any special C-One-Stuff Opcodes. The Risc needs about 500LC's of the FPGA and needs support RAM of 64Kb for the Z80 and 6502 Tables.
No idea, I'm not a Z80 guy :) However, the CPC core runs in the 1k30, the smaller of the two FPGAs, and is tuned towards performance and features rather than 100% compatibility (though it runs the games that I've tested). If someone was so inclined, they could put a cycle exact Z80 core with undocumented opcodes in the 1k100 for better compatibi- lity.
The startup system and the CPC-Cores works without a hardcoded Z80 in the 1K30. Currenly I'm working on a TurboCPC with Daniel Wallner's T80. The TurboCPC is an own Design for the big FPGA(1K100) on the C-One. The CPU clock is 16MHz.
look here http://c64upgra.de/c-one/download/cpc_study.zipThere is an early version of the core. I hope to finish the work on it in the end of february.
Gr��e Tobiflex