byuu says:
26 hours in, 173 instructions implemented. Although the four segment
prefix opcodes don't actually do anything yet. There's less than 256
actual instructions on the 80186, not sure of the exact count.
Gunpey gets around ~8,200 instructions in before hitting an unsupported
opcode (loop). Riviera goes off the rails on a retf and ends up
executing an endless stream of bad opcodes in RAM =( Both games hammer
the living shit out of the in/out ports pretty much immediately.
byuu says:
Man, the 80186 is taking a lot longer to implement than I thought it
would. So far I'm 18 hours into this emulator. Whereas I had Super Mario
Bros fully playable (no sound) in 12 hours for the NES >_>
I refactored all the byte/word variant functions to single functions
that take a size parameter. Cuts the amount of code in half.
Also implemented repz/repnz + movsb/movsw, so Riviera now gets 299
instructions in before dying. Nobody really bothers to explain how the
CPU actually implements these instructions, but I think I have it right:
ignore non-string opcodes that follow rep, invoke the string operations
inside the rep opcodes to prevent interrupts from triggering between the
two (which will be even more fun for segment selector overrides ...)
The next opcode needed is 0xC7, which ... throws ModRM on its head. In
this mode, ModRM is only used to determine the target operand (and it
doesn't use the middle bits for that at all), and the source is an
immediate that follows it. Gonna have to waste a few more hours thinking
about how best to handle that.
Also, disabled HiDPI for higan as well on OS X.
byuu says:
More V30MZ implemented, a lot more to go.
icarus now supports importing WS and WSC games. It expects them to have
the correct file extension, same for GB and GBC.
> Ugh, apparently HiDPI icarus doesn't let you press the check boxes.
I set the flag value in the plist to false for now. Forgot to do it for
higan, but hopefully I won't forget before release.
byuu says:
Lots of improvements. We're now able to start executing some V30MZ
instructions. 32 of 256 opcodes implemented so far.
I hope this goes without saying, but there's absolutely no point in
loading WS/WSC games right now. You won't see anything until I have the
full CPU and partial PPU implemented.
ROM bank 2 works properly now, the I/O map is 16-bit (address) x 16-bit
(data) as it should be*, and I have a basic disassembler in place
(adding to it as I emulate new opcodes.)
(* I don't know what happens if you access an 8-bit port in 16-bit mode
or vice versa, so for now I'm just treating the handlers as always being
16-bit, and discarding the upper 8-bits when not needed.)
byuu says:
So, this WIP starts work on something new for higan. Obviously, I can't
keep it a secret until it's ready, because I want to continue daily WIP
releases, and of course, solicit feedback as I go along.
Tim Allen