desiv wrote:
I'm looking at my Coleco Adam sitting underneath my Apple //e, and I'm thinking he might get even more jealous...
snip!
I studied how the Z80 softcard works many years ago and I think the 6502 was halted while the Z80 was working. The Apple' 6502 would 'wake up' to perform I/O and for short periods of time to refresh its registers which were built like dynamic RAM (needs refresh or it loses addresses for program counter and stack pointer!) In short, it was one processor at a time, plus they shared the same RAM.Interesting side note, if a Z80 port is viable, what would that mean for an Apple II with a CPM card?? Run 2 versions? 6502 and Z80? What about some of the other Z80 boxes out there??? Might be beyond me, but still interesting...
The memory map for the Z80 was all mixed up compared to the 6502 map to re-create the memory map of a CP/M system.
CP/M wasn't offering much service: serial and disk I/O (through BDOS) and a return-to-OS system call. Since CP/M offers I/O, I guess it wouldn't be too difficult to make Contiki use them.
My first C programs were done under CP/M with BDS-C (that's stands for Brain Damage Software). The BDS-C author made is compiler sources open to public. All in Z80 assembler: amazing!
Bringing CP/M to the Internet age: what a mad concept! Just like riding a donkey on the freeway :).
cheers! Yves