byuu says:
Added MBC1 emulation, although battery RAM doesn't save or load to disk
yet.
Made up a fake MBC0 which is really just saying 'no MBC', for consistent
handling of all MBCs.
Added bumpers to stop ROM/RAM out of bounds accesses.
Added STAT interrupts for LY coincidence, Vblank and Hblank (not for OAM
access yet, I don't know the timings.)
Fixed timer interrupt [Jonas Quinn]
Made all interrupts call a CPU function instead of just setting a flag
for better control (to allow below addition.)
Added HALT and STOP emulation, the latter permanently locks the Game Boy
for now. The former breaks on interrupts.
Rewrote all the rendering code to suck 50% less, though it's still
absolutely miserable and scanline-based.
Added pixel-level horizontal scrolling to BGs.
Fixed OBJ rendering error that was making them render upside down (I was
flipping to compensate before.)
Added OBJ 8x16 mode.
Added OBJ priority support.
Added window (but it's broken to all hell on Mega Man II.)
byuu says:
Fixed all of the previously mentioned problems by myself and Jonas
Quinn.
Fixed up JOYP and hooked up JOYP interrupts, they work on JOYP writes as
well if your selection makes the low four bits change to != 0xF.
Added basic sprite emulation, very very very lousy but it works for
Tetris.
Fixed DAA, fuck that opcode. Fixes blargg's CPU tests 1 and 11 (for some
odd reason.) Only test 2 is failing, on the "EI" test. Maybe it relies
on STAT interrupts?
Did some other stuff.
Tetris is now 100% fully playable. But that renderer is an abomination.
Soooooo simplistic and missing so many edge cases.
But holy shit, a fully playable commercial game in three days. I would
have killed to have made that progress when I started on bsnes.
byuu says:
All 512 instructions implemented. To make debugging flags easier and to
reduce the code size, I made parent routines for all the bit-logic that
sets flags. This bumped up the speed to 3,045fps. So about 51x faster
than a real Game Boy.
I suspect the frame rate to plummet rapidly as I emulate more stuff and
try and get timings more accurate. Wild ballpark, I'd guess 300fps or
so. Not based on anything, just a made up number. I have no idea what it
will end up being.
So I still need:
* decode MMIO reads/writes
* add CPU interrupt support
* add LCD emulation (probably the hardest part)
* add PCM emulation (well, this would likely be the hardest; but it's
not essential right now)
* debug the holy living shit out of the CPU core. Anyone want to help
now by looking it over? :D
byuu says:
314 of 512 opcodes implemented, can execute the first 67,450
instructions of Tetris.
I also added an MMIO bus, ala bsnes, so that I can map and access
individual registers with a single indirection.
byuu says:
Hooked up a scheduler to enter/exit the CPU core wherever I want. Added
basic 4*1024*1024hz clock, and about eleven or so opcodes. Creating the
disassembler as I encounter each new opcode, not skipping ahead to do
all 'like other' opcodes, eg if I add 'dec b', I don't then add 'dec c'
until I encounter it.
Tim Allen