byuu says:
Alright, well interrupts are in. At least Vblank is.
I also fixed a bug in vector() indexing, MoDRM mod!=3&®==6 using SS
instead of DS, opcodes a0-a3 allowing segment override, and added the
"irq_disable" stuff to the relevant opcodes to suppress IRQs after
certain instructions.
But unfortunately ... still no go on Riviera. It's not reading any
unmapped ports, and although it enables Vblank IRQs and they set port
$b4's status bit, the game never sets the IE flag, so no interrupts ever
actually fire. The game does indeed appear to be sitting in a rather
huge loop, which is probably dependent upon some RAM variable being set
from the Vblank IRQ, but I don't know how I'm supposed to be triggering
it.
... I'm really quite stumped here >_>
byuu says:
All 256 instructions implemented fully. Fixed a major bug with
instructions that both read and write to ModRM with displacement.
Riviera now runs into an infinite loop ... possibly crashed, possibly
waiting on interrupts or in to return something. Added a bunch of PPU
settings registers, but nothing's actually rendering with them yet.
244 of 256 opcodes implemented now, although the interrupt triggering
portions are missing from them still. Much better handling of prefixes
now.
I definitely have a newfound hatepreciation for x86 now >_>
byuu says:
Up to 211 opcodes implemented, with the caveat that the four opcodes
that make up group 3 and group 4 don't do anything yet. Both groups seem
to have some "illegal" instructions in them, so that'll be "fun".
I have a new mechanic in place for opcode prefixes, but it could use
some work still. I also only have it working to override ModRM mem
addressing, but of course it does it in a lot of other places like the
string operations.
Making it about 5.5 million instructions into Gunpey now, but of course
that doesn't mean much. Could be going off the rails at any point due to
CPU bugs or unimplemented ports. Riviera's still crashing.
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