View Single Post
  #2  
Old 12-15-2006, 09:12 PM
sje sje is offline
Member
 
Join Date: Nov 2006
Posts: 62
Default z80 caveat

I should also mention that I've made a reasonable effort in my emulator to implement all of the undocumented z80 opcodes to allow the widest variety of programs to run. However, some of these undocumented opcodes have different interpretations on differently sourced chips, so of course there's no promise that a particular non standard program will work.

Also, some 8080 code may not work properly on any z80, real or emulated. The original MITS Basic is reported to need patches for z80 operation, and there are surely more suspect programs. The main culprit is dependence on the parity flag bit behavior; Zilog thought that this was "broken" on the 8080, so they "fixed" it on the z80.
Reply With Quote