mirror of https://github.com/bsnes-emu/bsnes.git
10 Commits
| Author | SHA1 | Message | Date |
|---|---|---|---|
Tim Allen
|
55f19c3e0d |
Update to v103r32 release.
byuu says:
Changelog:
- Master System: merged Bus into CPU
- Mega Drive: merged BusCPU into CPU; BusAPU into AU
- Mega Drive: added TMSS emulation; disabled by default [hex\_usr]
- VDP lockout not yet emulated
- processor/arm7tdmi: renamed interrupt() to exception()
- processor/arm7tdmi: CPSR.F (FIQ disable) flag is set on reset
- processor/arm7tdmi: pipeline decode stage caches CPSR.T (THUMB mode)
[MerryMage]
- fixes `msr_tests.gba` test F
- processor/arm7tdmi/disassembler: add PC address to left of currently
executing instruction
- processor/arm7tdmi: stop forcing CPSR.M (mode flags) bit 4 high (I
don't know what really happens here)
- processor/arm7tdmi: undefined instructions now generate Undefined
0x4 exception
- processor/arm7tdmi: thumbInstructionAddRegister masks PC by &~3
instead of &~2
- hopefully this is correct; &~2 felt very wrong
- processor/arm7tdmi: thumbInstructionStackMultiple can use sequential
timing for PC/LR PUSH/POP [Cydrak]
- systems/Mega Drive.sys: added tmss.rom; enable with cpu version=1
- tomoko: detect when a ruby video/audio/input driver crashes higan;
disable it on next program startup
v104 blockers:
- Mega Drive: support 8-bit SRAM (even if we don't support 16-bit;
don't force 8-bit to 16-bit)
- Mega Drive: add region detection support to icarus
- ruby: add default audio device information so certain drivers won't
default to silence out of the box
|
|
|
Tim Allen
|
04072b278b |
Update to v102r16 release.
byuu says:
Changelog:
- Emulator::Stream now allows adding low-pass and high-pass filters
dynamically
- also accepts a pass# count; each pass is a second-order biquad
butterworth IIR filter
- Emulator::Stream no longer automatically filters out >20KHz
frequencies for all streams
- FC: added 20Hz high-pass filter; 20KHz low-pass filter
- GB: removed simple 'magic constant' high-pass filter of unknown
cutoff frequency (missed this one in the last WIP)
- GB,SGB,GBC: added 20Hz high-pass filter; 20KHz low-pass filter
- MS,GG,MD/PSG: added 20Hz high-pass filter; 20KHz low-pass filter
- MD: added save state support (but it's completely broken for now;
sorry)
- MD/YM2612: fixed Voice#3 per-operator pitch support (fixes sound
effects in Streets of Rage, etc)
- PCE: added 20Hz high-pass filter; 20KHz low-pass filter
- WS,WSC: added 20Hz high-pass filter; 20KHz low-pass filter
So, the point of the low-pass filters is to remove frequencies above
human hearing. If we don't do this, then resampling will introduce
aliasing that results in sounds that are audible to the human ear. Which
basically an annoying buzzing sound. You'll definitely hear the
improvement from these in games like Mega Man 2 on the NES. Of course,
these already existed before, so this WIP won't sound better than
previous WIPs.
The high-pass filters are a little more complicated. Their main role is
to remove DC bias and help to center the audio stream. I don't
understand how they do this at all, but ... that's what everyone who
knows what they're talking about says, thus ... so be it.
I have set all of the high-pass filters to 20Hz, which is below the
limit of human hearing. Now this is where it gets really interesting ...
technically, some of these systems actually cut off a lot of range. For
instance, the GBA should technically use an 800Hz high-pass filter when
output is done through the system's speakers. But of course, if you plug
in headphones, you can hear the lower frequencies.
Now 800Hz ... you definitely can hear. At that level, nearly all of the
bass is stripped out and the audio is very tinny. Just like the real
system. But for now, I don't want to emulate the audio being crushed
that badly.
I'm sticking with 20Hz everywhere since it won't negatively affect audio
quality. In fact, you should not be able to hear any difference between
this WIP and the previous WIP. But theoretically, DC bias should mostly
be removed as a result of these new filters. It may be that we need to
raise the values on some cores in the future, but I don't want to do
that until we know for certain that we have to.
What I can say is that compared to even older WIPs than r15 ... the
removal of the simple one-pole low-pass and high-pass filters with the
newer three-pass, second-order filters should result in much better
attenuation (less distortion of audible frequencies.) Probably not
enough to be noticeable in a blind test, though.
|
|
|
Tim Allen
|
fa6cbac251 |
Update to v102r06 release.
byuu says:
Changelog:
- added higan/emulator/platform.hpp (moved out Emulator::Platform from
emulator/interface.hpp)
- moved gmake build paramter to nall/GNUmakefile; both higan and
icarus use it now
- added build=profile mode
- MD: added the region select I/O register
- MD: started to add region selection support internally (still no
external select or PAL support)
- PCE: added cycle stealing when reading/writing to the VDC or VCE;
and when using ST# instructions
- PCE: cleaned up PSG to match the behavior of Mednafen (doesn't
improve sound at all ;_;)
- note: need to remove loadWaveSample, loadWavePeriod
- HuC6280: ADC/SBC decimal mode consumes an extra cycle; does not set
V flag
- HuC6280: block transfer instructions were taking one cycle too many
- icarus: added code to strip out PC Engine ROM headers
- hiro: added options support to BrowserDialog
The last one sure ended in failure. The plan was to put a region
dropdown directly onto hiro::BrowserDialog, and I had all the code for
it working. But I forgot one important detail: the system loads
cartridges AFTER powering on, so even though I could technically change
the system region post-boot, I'd rather not do so.
So that means we have to know what region we want before we even select
a game. Shit.
|
|
|
Tim Allen
|
bf90bdfcc8 |
Update to v101r31 release.
byuu says:
Changelog:
- converted Emulator::Interface::Bind to Emulator::Platform
- temporarily disabled SGB hooks
- SMS: emulated Game Gear palette (latching word-write behavior not
implemented yet)
- SMS: emulated Master System 'Reset' button, Game Gear 'Start' button
- SMS: removed reset() functionality, driven by the mappable input now
instead
- SMS: split interface class in two: one for Master System, one for
Game Gear
- SMS: emulated Game Gear video cropping to 160x144
- PCE: started on HuC6280 CPU core—so far only registers, NOP
instruction has been implemented
Errata:
- Super Game Boy support is broken and thus disabled
- if you switch between Master System and Game Gear without
restarting, bad things happen:
- SMS→GG, no video output on the GG
- GG→SMS, no input on the SMS
I'm not sure what's causing the SMS\<-\>GG switch bug, having a hard
time debugging it. Help would be very much appreciated, if anyone's up
for it. Otherwise I'll keep trying to track it down on my end.
|
|
|
Tim Allen
|
5df717ff2a |
Update to v101r12 release.
byuu says:
Changelog:
- new md/bus/ module for bus reads/writes
- abstracts byte/word accesses wherever possible (everything but
RAM; forces all but I/O to word, I/O to byte)
- holds the system RAM since that's technically not part of the
CPU anyway
- added md/controller and md/system/peripherals
- added emulation of gamepads
- added stub PSG audio output (silent) to cap the framerate at 60fps
with audio sync enabled
- fixed VSRAM reads for plane vertical scrolling (two bugs here: add
instead of sub; interlave plane A/B)
- mask nametable read offsets (can't exceed 8192-byte nametables
apparently)
- emulated VRAM/VSRAM/CRAM reads from VDP data port
- fixed sprite width/height size calculations
- added partial emulation of 40-tile per scanline limitation (enough
to fix Sonic's title screen)
- fixed off-by-one sprite range testing
- fixed sprite tile indexing
- Vblank happens at Y=224 with overscan disabled
- unsure what happens when you toggle it between Y=224 and Y=240
... probably bad things
- fixed reading of address register for ADDA, CMPA, SUBA
- fixed sign extension for MOVEA effect address reads
- updated MOVEM to increment the read addresses (but not writeback)
for (aN) mode
With all of that out of the way, we finally have Sonic the Hedgehog
(fully?) playable. I played to stage 1-2 and through the special stage,
at least. EDIT: yeah, we probably need HIRQs for Labyrinth Zone.
Not much else works, of course. Most games hang waiting on the Z80, and
those that don't (like Altered Beast) are still royally screwed. Tons of
features still missing; including all of the Z80/PSG/YM2612.
A note on the perihperals this time around: the Mega Drive EXT port is
basically identical to the regular controller ports. So unlike with the
Famicom and Super Famicom, I'm inheriting the exension port from the
controller class.
|
|
|
Tim Allen
|
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. |
|
|
Tim Allen
|
c50723ef61 |
Update to v100r15 release.
byuu wrote: Aforementioned scheduler changes added. Longer explanation of why here: http://hastebin.com/raw/toxedenece Again, we really need to test this as thoroughly as possible for regressions :/ This is a really major change that affects absolutely everything: all emulation cores, all coprocessors, etc. Also added ADDX and SUB to the 68K core, which brings us just barely above 50% of the instruction encoding space completed. [Editor's note: The "aformentioned scheduler changes" were described in a previous forum post: Unfortunately, 64-bits just wasn't enough precision (we were getting misalignments ~230 times a second on 21/24MHz clocks), so I had to move to 128-bit counters. This of course doesn't exist on 32-bit architectures (and probably not on all 64-bit ones either), so for now ... higan's only going to compile on 64-bit machines until we figure something out. Maybe we offer a "lower precision" fallback for machines that lack uint128_t or something. Using the booth algorithm would be way too slow. Anyway, the precision is now 2^-96, which is roughly 10^-29. That puts us far beyond the yoctosecond. Suck it, MAME :P I'm jokingly referring to it as the byuusecond. The other 32-bits of precision allows a 1Hz clock to run up to one full second before all clocks need to be normalized to prevent overflow. I fixed a serious wobbling issue where I was using clock > other.clock for synchronization instead of clock >= other.clock; and also another aliasing issue when two threads share a common frequency, but don't run in lock-step. The latter I don't even fully understand, but I did observe it in testing. nall/serialization.hpp has been extended to support 128-bit integers, but without explicitly naming them (yay generic code), so nall will still compile on 32-bit platforms for all other applications. Speed is basically a wash now. FC's a bit slower, SFC's a bit faster. The "longer explanation" in the linked hastebin is: Okay, so the idea is that we can have an arbitrary number of oscillators. Take the SNES: - CPU/PPU clock = 21477272.727272hz - SMP/DSP clock = 24576000hz - Cartridge DSP1 clock = 8000000hz - Cartridge MSU1 clock = 44100hz - Controller Port 1 modem controller clock = 57600hz - Controller Port 2 barcode battler clock = 115200hz - Expansion Port exercise bike clock = 192000hz Is this a pathological case? Of course it is, but it's possible. The first four do exist in the wild already: see Rockman X2 MSU1 patch. Manifest files with higan let you specify any frequency you want for any component. The old trick higan used was to hold an int64 counter for each thread:thread synchronization, and adjust it like so: - if thread A steps X clocks; then clock += X * threadB.frequency - if clock >= 0; switch to threadB - if thread B steps X clocks; then clock -= X * threadA.frequency - if clock < 0; switch to threadA But there are also system configurations where one processor has to synchronize with more than one other processor. Take the Genesis: - the 68K has to sync with the Z80 and PSG and YM2612 and VDP - the Z80 has to sync with the 68K and PSG and YM2612 - the PSG has to sync with the 68K and Z80 and YM2612 Now I could do this by having an int64 clock value for every association. But these clock values would have to be outside the individual Thread class objects, and we would have to update every relationship's clock value. So the 68K would have to update the Z80, PSG, YM2612 and VDP clocks. That's four expensive 64-bit multiply-adds per clock step event instead of one. As such, we have to account for both possibilities. The only way to do this is with a single time base. We do this like so: - setup: scalar = timeBase / frequency - step: clock += scalar * clocks Once per second, we look at every thread, find the smallest clock value. Then subtract that value from all threads. This prevents the clock counters from overflowing. Unfortunately, these oscillator values are psychotic, unpredictable, and often times repeating fractions. Even with a timeBase of 1,000,000,000,000,000,000 (one attosecond); we get rounding errors every ~16,300 synchronizations. Specifically, this happens with a CPU running at 21477273hz (rounded) and SMP running at 24576000hz. That may be good enough for most emulators, but ... you know how I am. Plus, even at the attosecond level, we're really pushing against the limits of 64-bit integers. Given the reciprocal inverse, a frequency of 1Hz (which does exist in higan!) would have a scalar that consumes 1/18th of the entire range of a uint64 on every single step. Yes, I could raise the frequency, and then step by that amount, I know. But I don't want to have weird gotchas like that in the scheduler core. Until I increase the accuracy to about 100 times greater than a yoctosecond, the rounding errors are too great. And since the only choice above 64-bit values is 128-bit values; we might as well use all the extra headroom. 2^-96 as a timebase gives me the ability to have both a 1Hz and 4GHz clock; and run them both for a full second; before an overflow event would occur. Another hastebin includes demonstration code: #include <libco/libco.h> #include <nall/nall.hpp> using namespace nall; // cothread_t mainThread = nullptr; const uint iterations = 100'000'000; const uint cpuFreq = 21477272.727272 + 0.5; const uint smpFreq = 24576000.000000 + 0.5; const uint cpuStep = 4; const uint smpStep = 5; // struct ThreadA { cothread_t handle = nullptr; uint64 frequency = 0; int64 clock = 0; auto create(auto (*entrypoint)() -> void, uint frequency) { this->handle = co_create(65536, entrypoint); this->frequency = frequency; this->clock = 0; } }; struct CPUA : ThreadA { static auto Enter() -> void; auto main() -> void; CPUA() { create(&CPUA::Enter, cpuFreq); } } cpuA; struct SMPA : ThreadA { static auto Enter() -> void; auto main() -> void; SMPA() { create(&SMPA::Enter, smpFreq); } } smpA; uint8 queueA[iterations]; uint offsetA; cothread_t resumeA = cpuA.handle; auto EnterA() -> void { offsetA = 0; co_switch(resumeA); } auto QueueA(uint value) -> void { queueA[offsetA++] = value; if(offsetA >= iterations) { resumeA = co_active(); co_switch(mainThread); } } auto CPUA::Enter() -> void { while(true) cpuA.main(); } auto CPUA::main() -> void { QueueA(1); smpA.clock -= cpuStep * smpA.frequency; if(smpA.clock < 0) co_switch(smpA.handle); } auto SMPA::Enter() -> void { while(true) smpA.main(); } auto SMPA::main() -> void { QueueA(2); smpA.clock += smpStep * cpuA.frequency; if(smpA.clock >= 0) co_switch(cpuA.handle); } // struct ThreadB { cothread_t handle = nullptr; uint128_t scalar = 0; uint128_t clock = 0; auto print128(uint128_t value) { string s; while(value) { s.append((char)('0' + value % 10)); value /= 10; } s.reverse(); print(s, "\n"); } //femtosecond (10^15) = 16306 //attosecond (10^18) = 688838 //zeptosecond (10^21) = 13712691 //yoctosecond (10^24) = 13712691 (hitting a dead-end on a rounding error causing a wobble) //byuusecond? ( 2^96) = (perfect? 79,228 times more precise than a yoctosecond) auto create(auto (*entrypoint)() -> void, uint128_t frequency) { this->handle = co_create(65536, entrypoint); uint128_t unitOfTime = 1; //for(uint n : range(29)) unitOfTime *= 10; unitOfTime <<= 96; //2^96 time units ... this->scalar = unitOfTime / frequency; print128(this->scalar); this->clock = 0; } auto step(uint128_t clocks) -> void { clock += clocks * scalar; } auto synchronize(ThreadB& thread) -> void { if(clock >= thread.clock) co_switch(thread.handle); } }; struct CPUB : ThreadB { static auto Enter() -> void; auto main() -> void; CPUB() { create(&CPUB::Enter, cpuFreq); } } cpuB; struct SMPB : ThreadB { static auto Enter() -> void; auto main() -> void; SMPB() { create(&SMPB::Enter, smpFreq); clock = 1; } } smpB; auto correct() -> void { auto minimum = min(cpuB.clock, smpB.clock); cpuB.clock -= minimum; smpB.clock -= minimum; } uint8 queueB[iterations]; uint offsetB; cothread_t resumeB = cpuB.handle; auto EnterB() -> void { correct(); offsetB = 0; co_switch(resumeB); } auto QueueB(uint value) -> void { queueB[offsetB++] = value; if(offsetB >= iterations) { resumeB = co_active(); co_switch(mainThread); } } auto CPUB::Enter() -> void { while(true) cpuB.main(); } auto CPUB::main() -> void { QueueB(1); step(cpuStep); synchronize(smpB); } auto SMPB::Enter() -> void { while(true) smpB.main(); } auto SMPB::main() -> void { QueueB(2); step(smpStep); synchronize(cpuB); } // #include <nall/main.hpp> auto nall::main(string_vector) -> void { mainThread = co_active(); uint masterCounter = 0; while(true) { print(masterCounter++, " ...\n"); auto A = clock(); EnterA(); auto B = clock(); print((double)(B - A) / CLOCKS_PER_SEC, "s\n"); auto C = clock(); EnterB(); auto D = clock(); print((double)(D - C) / CLOCKS_PER_SEC, "s\n"); for(uint n : range(iterations)) { if(queueA[n] != queueB[n]) return print("fail at ", n, "\n"); } } } ...and that's everything.] |
|
|
Tim Allen
|
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.
|
|
|
Tim Allen
|
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. |
|
|
Tim Allen
|
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. |