mirror of https://github.com/bsnes-emu/bsnes.git
3 Commits
| Author | SHA1 | Message | Date |
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Tim Allen
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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
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Tim Allen
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3517d5c4a4 |
Update to v103r02 release.
byuu says:
Changelog:
- fc/apu: improved phase duty cycle emulation (mode 3 is 25% phase
inverted; counter decrements)
- md/apu: power/reset do not cancel 68K bus requests
- md/apu: 68K is not granted bus access on Z80 power/reset
- md/controller: replaced System::Peripherals with ControllerPort
concept
- md/controller: CTRL port is now read-write, maintains value across
controller changes (and soon, soft resets)
- md/psg: PSG sampling rate unintentionally modified¹
- processor/spc700: improve cycle timing of (indirect),y instructions
[Overload]
- processor/spc700: idle() cycles actually read from the program
counter; much like the 6502 [Overload]
- some of the idle() cycles should read from other addresses; this
still needs to be supported
- processor/spc700: various cleanups to instruction function naming
- processor/z80: prefix state (HL→IX,IY override) can now be
serialized
- icarus: fix install rule for certain platforms (it wasn't buggy on
FreeBSD, but was on Linux?)
¹: the clock speed of the PSG is oscillator/15. But I was setting the
sampling rate to oscillator/15/16, which was around 223KHz. I am not
sure whether the PSG should be outputting at 3MHz or 223KHz. Amazingly
... I don't really hear a difference either way `o_O` I didn't actually
mean to make this change; I just noticed it after comparing the diff
between r01 and r02. If this turns out to be wrong, set
stream = Emulator::audio.createStream(1, frequency() / 16.0);
in md/psg.cpp to revert this change.
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Tim Allen
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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.
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