mirror of https://github.com/bsnes-emu/bsnes.git
7 Commits
| Author | SHA1 | Message | Date |
|---|---|---|---|
Tim Allen
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043f6a8b33 |
Update to v101r08 release.
byuu says:
Changelog:
- 68K: fixed read-modify-write instructions
- 68K: fixed ADDX bug (using wrong target)
- 68K: fixed major bug with SUB using wrong argument ordering
- 68K: fixed sign extension when reading address registers from
effective addressing
- 68K: fixed sign extension on CMPA, SUBA instructions
- VDP: improved OAM sprite attribute table caching behavior
- VDP: improved DMA fill operation behavior
- added Master System / Game Gear stubs (needed for developing the Z80
core)
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Tim Allen
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ffd150735b |
Update to v101r07 release.
byuu says: Added VDP sprite rendering. Can't get any games far enough in to see if it actually works. So in other words, it doesn't work at all and is 100% completely broken. Also added 68K exceptions and interrupts. So far only the VDP interrupt is present. It definitely seems to be firing in commercial games, so that's promising. But the implementation is almost certainly completely wrong. There is fuck all of nothing for documentation on how interrupts actually work. I had to find out the interrupt vector numbers from reading the comments from the Sonic the Hedgehog disassembly. I have literally no fucking clue what I0-I2 (3-bit integer priority value in the status register) is supposed to do. I know that Vblank=6, Hblank=4, Ext(gamepad)=2. I know that at reset, SR.I=7. I don't know if I'm supposed to block interrupts when I is >, >=, <, <= to the interrupt level. I don't know what level CPU exceptions are supposed to be. Also implemented VDP regular DMA. No idea if it works correctly since none of the commercial games run far enough to use it. So again, it's horribly broken for usre. Also improved VDP fill mode. But I don't understand how it takes byte-lengths when the bus is 16-bit. The transfer times indicate it's actually transferring at the same speed as the 68K->VDP copy, strongly suggesting it's actually doing 16-bit transfers at a time. In which case, what happens when you set an odd transfer length? Also, both DMA modes can now target VRAM, VSRAM, CRAM. Supposedly there's all kinds of weird shit going on when you target VSRAM, CRAM with VDP fill/copy modes, but whatever. Get to that later. Also implemented a very lazy preliminary wait mechanism to to stall out a processor while another processor exerts control over the bus. This one's going to be a major work in progress. For one, it totally breaks the model I use to do save states with libco. For another, I don't know if a 68K->VDP DMA instantly locks the CPU, or if it the CPU could actually keep running if it was executing out of RAM when it started the DMA transfer from ROM (eg it's a bus busy stall, not a hard chip stall.) That'll greatly change how I handle the waiting. Also, the OSS driver now supports Audio::Latency. Sound should be even lower latency now. On FreeBSD when set to 0ms, it's absolutely incredible. Cannot detect latency whatsoever. The Mario jump sound seems to happen at the very instant I hear my cherry blue keyswitch activate. |
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Tim Allen
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ac2d0ba1cf |
Update to v101r05 release.
byuu says:
Changelog:
- 68K: fixed bug that affected BSR return address
- VDP: added very preliminary emulation of planes A, B, W (W is
entirely broken though)
- VDP: added command/address stuff so you can write to VRAM, CRAM,
VSRAM
- VDP: added VRAM fill DMA
I would be really surprised if any commercial games showed anything at
all, so I'd probably recommend against wasting your time trying, unless
you're really bored :P
Also, I wanted to add: I am accepting patches\! So if anyone wants to
look over the 68K core for bugs, that would save me untold amounts of
time in the near future :D
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Tim Allen
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1df2549d18 |
Update to v101r04 release.
byuu says:
Changelog:
- pulled the (u)intN type aliases into higan instead of leaving them
in nall
- added 68K LINEA, LINEF hooks for illegal instructions
- filled the rest of the 68K lambda table with generic instance of
ILLEGAL
- completed the 68K disassembler effective addressing modes
- still unsure whether I should use An to decode absolute
addresses or not
- pro: way easier to read where accesses are taking place
- con: requires An to be valid; so as a disassembler it does a
poor job
- making it optional: too much work; ick
- added I/O decoding for the VDP command-port registers
- added skeleton timing to all five processor cores
- output at 1280x480 (needed for mixed 256/320 widths; and to handle
interlace modes)
The VDP, PSG, Z80, YM2612 are all stepping one clock at a time and
syncing; which is the pathological worst case for libco. But they also
have no logic inside of them. With all the above, I'm averaging around
250fps with just the 68K core actually functional, and the VDP doing a
dumb "draw white pixels" loop. Still way too early to tell how this
emulator is going to perform.
Also, the 320x240 mode of the Genesis means that we don't need an aspect
correction ratio. But we do need to ensure the output window is a
multiple 320x240 so that the scale values work correctly. I was
hard-coding aspect correction to stretch the window an additional \*8/7.
But that won't work anymore so ... the main higan window is now 640x480,
960x720, or 1280x960. Toggling aspect correction only changes the video
width inside the window.
It's a bit jarring ... the window is a lot wider, more black space now
for most modes. But for now, it is what it is.
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Tim Allen
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ca277cd5e8 |
Update to v100r14 release.
byuu says:
(Windows: compile with -fpermissive to silence an annoying error. I'll
fix it in the next WIP.)
I completely replaced the time management system in higan and overhauled
the scheduler.
Before, processor threads would have "int64 clock"; and there would
be a 1:1 relationship between two threads. When thread A ran for X
cycles, it'd subtract X * B.Frequency from clock; and when thread B ran
for Y cycles, it'd add Y * A.Frequency from clock. This worked well
and allowed perfect precision; but it doesn't work when you have more
complicated relationships: eg the 68K can sync to the Z80 and PSG; the
Z80 to the 68K and PSG; so the PSG needs two counters.
The new system instead uses a "uint64 clock" variable that represents
time in attoseconds. Every time the scheduler exits, it subtracts
the smallest clock count from all threads, to prevent an overflow
scenario. The only real downside is that rounding errors mean that
roughly every 20 minutes, we have a rounding error of one clock cycle
(one 20,000,000th of a second.) However, this only applies to systems
with multiple oscillators, like the SNES. And when you're in that
situation ... there's no such thing as a perfect oscillator anyway. A
real SNES will be thousands of times less out of spec than 1hz per 20
minutes.
The advantages are pretty immense. First, we obviously can now support
more complex relationships between threads. Second, we can build a
much more abstracted scheduler. All of libco is now abstracted away
completely, which may permit a state-machine / coroutine version of
Thread in the future. We've basically gone from this:
auto SMP::step(uint clocks) -> void {
clock += clocks * (uint64)cpu.frequency;
dsp.clock -= clocks;
if(dsp.clock < 0 && !scheduler.synchronizing()) co_switch(dsp.thread);
if(clock >= 0 && !scheduler.synchronizing()) co_switch(cpu.thread);
}
To this:
auto SMP::step(uint clocks) -> void {
Thread::step(clocks);
synchronize(dsp);
synchronize(cpu);
}
As you can see, we don't have to do multiple clock adjustments anymore.
This is a huge win for the SNES CPU that had to update the SMP, DSP, all
peripherals and all coprocessors. Likewise, we don't have to synchronize
all coprocessors when one runs, now we can just synchronize the active
one to the CPU.
Third, when changing the frequencies of threads (think SGB speed setting
modes, GBC double-speed mode, etc), it no longer causes the "int64
clock" value to be erroneous.
Fourth, this results in a fairly decent speedup, mostly across the
board. Aside from the GBA being mostly a wash (for unknown reasons),
it's about an 8% - 12% speedup in every other emulation core.
Now, all of this said ... this was an unbelievably massive change, so
... you know what that means >_> If anyone can help test all types of
SNES coprocessors, and some other system games, it'd be appreciated.
----
Lastly, we have a bitchin' new about screen. It unfortunately adds
~200KiB onto the binary size, because the PNG->C++ header file
transformation doesn't compress very well, and I want to keep the
original resource files in with the higan archive. I might try some
things to work around this file size increase in the future, but for now
... yeah, slightly larger archive sizes, sorry.
The logo's a bit busted on Windows (the Label control's background
transparency and alignment settings aren't working), but works well on
GTK. I'll have to fix Windows before the next official release. For now,
look on my Twitter feed if you want to see what it's supposed to look
like.
----
EDIT: forgot about ICD2::Enter. It's doing some weird inverse
run-to-save thing that I need to implement support for somehow. So, save
states on the SGB core probably won't work with this WIP.
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Tim Allen
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76a8ecd32a |
Update to v100r03 release.
byuu says: Changelog: - moved Thread, Scheduler, Cheat functionality into emulator/ for all cores - start of actual Mega Drive emulation (two 68K instructions) I'm going to be rather terse on MD emulation, as it's too early for any meaningful dialogue here. |
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Tim Allen
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3dd1aa9c1b |
Update to v100r02 release.
byuu says: Sigh ... I'm really not a good person. I'm inherently selfish. My responsibility and obligation right now is to work on loki, and then on the Tengai Makyou Zero translation, and then on improving the Famicom emulation. And yet ... it's not what I really want to do. That shouldn't matter; I should work on my responsibilities first. Instead, I'm going to be a greedy, self-centered asshole, and work on what I really want to instead. I'm really sorry, guys. I'm sure this will make a few people happy, and probably upset even more people. I'm also making zero guarantees that this ever gets finished. As always, I wish I could keep these things secret, so if I fail / give up, I could just drop it with no shame. But I would have to cut everyone out of the WIP process completely to make it happen. So, here goes ... This WIP adds the initial skeleton for Sega Mega Drive / Genesis emulation. God help us. (minor note: apparently the new extension for Mega Drive games is .md, neat. That's what I chose for the folders too. I thought it was .smd, so that'll be fixed in icarus for the next WIP.) (aside: this is why I wanted to get v100 out. I didn't want this code in a skeleton state in v100's source. Nor did I want really broken emulation, which the first release is sure to be, tarring said release.) ... So, basically, I've been ruminating on the legacy I want to leave behind with higan. 3D systems are just plain out. I'm never going to support them. They're too complex for my abilities, and they would run too slowly with my design style. I'm not willing to compromise my design ideals. And I would never want to play a 3D game system at native 240p/480i resolution ... but 1080p+ upscaling is not accurate, so that's a conflict I want to avoid entirely. It's also never going to emulate computer systems (X68K, PC-98, FM-Towns, etc) because holy shit that would completely destroy me. It's also never going emulate arcade machines. So I think of higan as a collection of 2D emulators for consoles and handhelds. I've gone over every major 2D gaming system there is, looking for ones with games I actually care about and enjoy. And I basically have five of those systems supported already. Looking at the remaining list, I see only three systems left that I have any interest in whatsoever: PC-Engine, Master System, Mega Drive. Again, I'm not in any way committing to emulating any of these, but ... if I had all of those in higan, I think I'd be content to really, truly, finally stop writing more emulators for the rest of my life. And so I decided to tackle the most difficult system first. If I'm successful, the Z80 core should cover a lot of the work on the SMS. And the HuC6280 should land somewhere between the NES and SNES in terms of difficulty ... closer to the NES. The systems that just don't appeal to me at all, which I will never touch, include, but are not limited to: * Atari 2600/5200/7800 * Lynx * Jaguar * Vectrex * Colecovision * Commodore 64 * Neo-Geo * Neo-Geo Pocket / Color * Virtual Boy * Super A'can * 32X * CD-i * etc, etc, etc. And really, even if something were mildly interesting in there ... we have to stop. I can't scale infinitely. I'm already way past my limit, but I'm doing this anyway. Too many cores bloats everything and kills quality on everything. I don't want higan to become MESS v2. I don't know what I'll do about the Famicom Disk System, PC-Engine CD, and Mega CD. I don't think I'll be able to achieve 60fps emulating the Mega CD, even if I tried to. I don't know what's going to happen here with even the Mega Drive. Maybe I'll get driven crazy with the documentation and quit. Maybe it'll end up being too complicated and I'll quit. Maybe the emulation will end up way too slow and I'll give up. Maybe it'll take me seven years to get any games playable at all. Maybe Steve Snake, AamirM and Mike Pavone will pool money to hire a hitman to come after me. Who knows. But this is what I want to do, so ... here goes nothing. |