mirror of https://github.com/bsnes-emu/bsnes.git
20 Commits
| Author | SHA1 | Message | Date |
|---|---|---|---|
Tim Allen
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d621136d69 |
Update to v104r04 release.
byuu says:
Changelog:
- higan/emulator: added new Random class with three entropy settings:
none, low, and high
- md/vdp: corrected Vcounter readout in interlace mode [MoD]
- sfc: updated core to use the new Random class; defaults to high
entropy
No entropy essentially returns 0, unless the random.bias(n) function is
called, in which case, it returns n. In this case, n is meant to be the
"logical/ideal" default value that maximizes compatibility with games.
Low entropy is a very simple entropy modeled after RAM initialization
striping patterns (eg 32 0x00s, followed by 32 0xFFs, repeating
throughout.) It doesn't "glitch" like real hardware does on rare
occasions (parts of the pattern being broken from time to time.) It also
only really returns 0 or ~0. So the entropy is indeed extremely low, and
not very useful at all for detecting bugs. Over time, we can try to
improve this, of course.
High entropy is PCG. This replaces the older, lower-entropy and more
predictable, LFSR. PCG should be more than enough for emulator
randomness, while still being quite fast.
Unfortunately, the bad news ... both no entropy and low entropy fix the
Konami logo popping sound in Prince of Persia, but all three entropy
settings still cause the distortion in-game, especially evident at the
title screen. So ... this may be a more serious bug than first
suspected.
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Tim Allen
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d13f1dd9ea |
Update to v104r03 release.
byuu says:
Changelog:
- md/vdp: added full interlace emulation [byuu, Sik, Eke, Mask of
Destiny]
- md/vdp: fix an issue with overscan/highlight when setting was
disabled [hex\_usr]
- md/vdp: serialize field, and all oam/objects state
- icarus/md: do not enable RAM unless header 0x1b0-1b1 == "RA"
[hex\_usr]
I really can't believe how difficult the interlace support was to add. I
must have tried a hundred combinations of adjusting Y, Vscroll, tile
addressing, heights, etc. Many of the changes were a wash that improved
some things, regressed others.
In the end I ended up needing input from three different people to
implement what should have been trivial. I don't know if the Mega Drive
is just that weird, if I've declined that much in skill since the days
when I implemented SNES interlace, or if I've just never been that good.
But either way, I'm disappointed in myself for not being able to figure
either this or shadow/highlight out on my own. Yet I'm extremely
grateful to my friends for helping carry me when I get stuck.
Since it wasn't ever documented before, I'm going to try and document
the changes necessary to implement interlace mode for any future
emudevs.
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Tim Allen
|
11357169a5 |
Update to v104r02 release.
byuu says:
Changelog:
- md/vdp: backgrounds always update priority bit output [Cydrak]
- md/vdp: vcounter.d0 becomes vcounter.d8 in interlace mode 3
- md/vdp: return field number in interlace modes from status register
- md/vdp: rework scanline/frame counting in main loop so first frame
won't clock to field 1 instead of field 0
- md/vdp: add support for shadow/highlight mode; optimize to minimal
code [Cydrak]
- md/vdp: update outputPixel() to support interlace modes
- sfc/cpu: auto joypad polling start should clear the shift registers;
fixes Nuke (PD)
- thanks to BMF54123 for this bug report
- tomoko: if an invalid video/audio/input driver is found in the
configuration file, it's reset to "None"
- prevents showing the wrong driver under advanced settings; no
longer requires possibly two reboots to fix
Note: the Mega Drive interlace mode 1 should be working fully, but I
don't know any games that use it. Interlace mode 3 (Sonic 2's two-player
mode) does not work at all yet, but this is a good start.
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Tim Allen
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80841deaa5 |
Update to v103r21 release.
byuu says:
Changelog:
- gb: added TAMA emulation [thanks to endrift for the initial notes]
- gb: save RTC memory to disk (MBC3 doesn't write to said memory yet;
TAMA doesn't emulate it yet)
- gb: expect MMM01 boot loader to be at end of ROM instead of start
- gb: store MBC2 save RAM as 256-bytes (512x4-bit) instead of
512-bytes (with padding)
- gb: major cleanups to every cartridge mapper; moved to Mapper class
instead of MMIO class
- gb: don't serialize all mapper states with every save state; only
serialize the active mapper
- gb: serialize RAM even if a battery isn't present¹
- gb/cartridge: removed unnecessary code; refactored other code to
eliminate duplication of functions
- icarus: improve GB(C) heuristics generation to not include filenames
for cartridges without battery backup
- icarus: remove incorrect rearrangement of MMM01 ROM data
- md/vdp: fix CRAM reads -- fixes Sonic Spinball colors [hex\_usr]
- tomoko: hide the main higan window when entering fullscreen
exclusive mode; helps with multi-monitor setups
- tomoko: destroy ruby drivers before calling Application::quit()
[Screwtape]
- libco: add settings.h and defines to fiber, ucontext [Screwtape]
¹: this is one of those crystal clear indications that nobody's
actually playing the higan DMG/CGB cores, or at least not with save
states. This was a major mistake.
Note: I can't find any official documentation that `GL_ALPHA_TEST` was
removed from OpenGL 3.2. Since it's not hurting anything except showing
some warnings in debug mode, I'm just going to leave it there for now.
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Tim Allen
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ecc7e899e0 |
Update to v103r01 release.
byuu says:
Changelog:
- nall/dsp: improve one pole coefficient calculations [Fatbag]
- higan/audio: reworked filters to support selection of either one
pole (first-order) or biquad (second-order) filters
- note: the design is not stable yet; so forks should not put too
much effort into synchronizing with this change yet
- fc: added first-order filters as per NESdev wiki (90hz lowpass +
440hz lowpass + 14khz highpass)
- fc: created separate NTSC-J and NTSC-U regions
- NESdev wiki says the Japanese Famicom uses a separate audio
filtering strategy, but details are fuzzy
- there's also cartridge audio output being disabled on NES units;
and differences with controllers
- this stuff will be supported in the future, just adding the
support for it now
- gba: corrected serious bugs in PSG wave channel emulation [Cydrak]
- note that if there are still bugs here, it's my fault
- md/psg,ym2612: added first-order low-pass 2840hz filter to match
VA3-VA6 Mega Drives
- md/psg: lowered volume relative to the YM2612
- using 0x1400; multiple people agreed it was the closest to the
hardware recordings against a VA6
- ms,md/psg: don't serialize the volume levels array
- md/vdp: Hblank bit acts the same during Vblank as outside of it (it
isn't always set during Vblank)
- md/vdp: return isPAL in bit 0 of control port reads
- tomoko: change command-line option separator from : to |
- [Editor's note: This change was present in the public v103,
but it's in this changelog because it was made after the v103 WIP]
- higan/all: change the 20hz high-pass filters from second-order
three-pass to first-order one-pass
- these filters are meant to remove DC bias, but I honestly can't
hear a difference with or without them
- so there's really no sense wasting CPU power with an extremely
powerful filter here
Things I did not do:
- change icarus install rule
- work on 8-bit Mega Drive SRAM
- work on Famicom or Mega Drive region detection heuristics in icarus
My long-term dream plan is to devise a special user-configurable
filtering system where you can set relative volumes and create your own
list of filters (any number of them in any order at any frequency), that
way people can make the systems sound however they want.
Right now, the sanest place to put this information is inside the
$system.sys/manifest.bml files. But that's not very user friendly, and
upgrading to new versions will lose these changes if you don't copy them
over manually. Of course, cluttering the GUI with a fancy filter editor
is probably supreme overkill for 99% of users, so maybe that's fine.
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Tim Allen
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8476f35153 |
Update to v102r28 release.
byuu says:
Changelog:
- higan: `Emulator::<Platform::load>()` now returns a struct containing
both a path ID and a string option
- higan: `Emulator::<Platform::load>()` now takes an optional final
argument of string options
- fc: added PAL emulation (finally, only took six years)
- md: added PAL emulation
- md: fixed address parameter to `VDP::Sprite::write()`; fixes missing
sprites in Super Street Fighter II
- md: emulated HIRQ counter; fixes many games
- Super Street Fighter II - status bar
- Altered Beast - status bar
- Sonic the Hedgehog - Labyrinth Zone - water effect
- etc.
- ms: added PAL emulation
- sfc: added the ability to override the default region auto-detection
- sfc: removed "system.region" override setting from `Super Famicom.sys`
- tomoko: added options list to game folder load dialog window
- tomoko: added the ability to specify game folder load options on the
command-line
So, basically ... Sega forced a change with the way region detection
works. You end up with games that can run on multiple regions, and the
content changes accordingly. Bare Knuckle in NTSC-J mode will become
Streets of Rage in NTSC-U mode. Some games can even run in both NTSC and
PAL mode.
In my view, there should be a separate ROM for each region a game was
released in, even if the ROM content were identical. But unfortunately
that's not how things were done by anyone else.
So to support this, the higan load dialog now has a drop-down at the
bottom-right, where you can choose the region to load games from. On the
SNES, it defaults to "Auto", which will pull the region setting from the
manifest, or fall back on NTSC. On the Mega Drive ... unfortunately, I
can't auto-detect the region from the ROM header. $1f0 is supposed to
contain a string like "JUE", but instead you get games like Maui Mallard
that put an "A" there, and other such nonsense. Sega was far more lax
than Nintendo with the ROM header validity. So for now at least, you
have to manually select your region every time you play a Mega Drive
game, thus you have "NTSC-J", "NTSC-U", and "PAL". The same goes for the
Master System for the same reason, but there's only "NTSC" and "PAL"
here. I'm not sure if games have a way to detect domestic vs
international consoles.
And for now ... the Famicom is the same as well, with no auto-detection.
I'd sincerely hope iNES has a header bit for the region, but I didn't
bother with updating icarus to support that yet.
The way to pass these parameters on the command-line is to prefix the
game path with "option:", so for example:
higan "PAL:/path/to/Sonic the Hedgehog (USA, Europe).md"
If you don't provide a prefix, it uses the default (NTSC-J, NTSC, or
Auto.) Obviously, it's not possible to pass parameters with
drag-and-drop, so you will always get the default option in said case.
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Tim Allen
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6e8406291c |
Update to v102r24 release.
byuu says
Changelog:
- FC: fixed three MOS6502 regressions [hex\_usr]
- GBA: return fetched instruction instead of 0 for unmapped MMIO
(passes all of endrift's I/O tests)
- MD: fix VDP control port read Vblank bit to test screen height
instead of hard-code 240 (fixes Phantasy Star IV)
- MD: swap USP,SSP when executing an exception (allows Super Street
Fighter II to run; but no sprites visible yet)
- MD: grant 68K access to Z80 bus on reset (fixes vdpdoc demo ROM from
freezing immediately)
- SFC: reads from $00-3f,80-bf:4000-43ff no longer update MDR
[p4plus2]
- SFC: massive, eight-hour cleanup of WDC65816 CPU core ... still not
complete
The big change this time around is the SFC CPU core. I've renamed
everything from R65816 to WDC65816, and then went through and tried to
clean up the code as much as possible. This core is so much larger than
the 6502 core that I chose cleaning up the code to rewriting it.
First off, I really don't care for the BitRange style functionality. It
was an interesting experiment, but its fatal flaw are that the types are
just bizarre, which makes them hard to pass around generically to other
functions as arguments. So I went back to the list of bools for flags,
and union/struct blocks for the registers.
Next, I renamed all of the functions to be more descriptive: eg
`op_read_idpx_w` becomes `instructionIndexedIndirectRead16`. `op_adc_b`
becomes `algorithmADC8`. And so forth.
I eliminated about ten instructions because they were functionally
identical sans the index, so I just added a uint index=0 parameter to
said functions. I added a few new ones (adjust→INC,DEC;
pflag→REP,SEP) where it seemed appropriate.
I cleaned up the disaster of the instruction switch table into something
a whole lot more elegant without all the weird argument decoding
nonsense (still need M vs X variants to avoid having to have 4-5
separate switch tables, but all the F/I flags are gone now); and made
some things saner, like the flag clear/set and branch conditions, now
that I have normal types for flags and registers once again.
I renamed all of the memory access functions to be more descriptive to
what they're doing: eg writeSP→push, readPC→fetch,
writeDP→writeDirect, etc. Eliminated some of the special read/write
modes that were only used in one single instruction.
I started to clean up some of the actual instructions themselves, but
haven't really accomplished much here. The big thing I want to do is get
rid of the global state (aa, rd, iaddr, etc) and instead use local
variables like I am doing with my other 65xx CPU cores now. But this
will take some time ... the algorithm functions depend on rd to be set
to work on them, rather than taking arguments. So I'll need to rework
that.
And then lastly, the disassembler is still a mess. I want to finish the
CPU cleanups, and then post a new WIP, and then rewrite the disassembler
after that. The reason being ... I want a WIP that can generate
identical trace logs to older versions, in case the CPU cleanup causes
any regressions. That way I can more easily spot the errors.
Oh ... and a bit of good news. v102 was running at ~140fps on the SNES
core. With the new support to suspend/resume WAI/STP, plus the internal
CPU registers not updating the MDR, the framerate dropped to ~132fps.
But with the CPU cleanups, performance went back to ~140fps. So, hooray.
Of course, without those two other improvements, we'd have ended up at
possibly ~146-148fps, but oh well.
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Tim Allen
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82c58527c3 |
Update to v102r17 release.
byuu says:
Changelog:
- GBA: process audio at 2MHz instead of 32KHz¹
- MD: do not allow the 68K to stop the Z80, unless it has been granted
bus access first
- MD: do not reset bus requested/granted signals when the 68K resets
the Z80
- the above two fix The Lost Vikings
- MD: clean up the bus address decoding to be more readable
- MD: add support for a13000-a130ff (#TIME) region; pass to cartridge
I/O²
- MD: emulate SRAM mapping used by >16mbit games; bank mapping used
by >32mbit games³
- MD: add 'reset pending' flag so that loading save states won't
reload 68K PC, SP registers
- this fixes save state support ... mostly⁴
- MD: if DMA is not enabled, do not allow CD5 to be set [Cydrak]
- this fixes in-game graphics for Ristar. Title screen still
corrupted on first run
- MD: detect and break sprite lists that form an infinite loop
[Cydrak]
- this fixes the emulator from dead-locking on certain games
- MD: add DC offset to sign DAC PCM samples [Cydrak]
- this improves audio in Sonic 3
- MD: 68K TAS has a hardware bug that prevents writing the result back
to RAM
- this fixes Gargoyles
- MD: 68K TRAP should not change CPU interrupt level
- this fixes Shining Force II, Shining in the Darkness, etc
- icarus: better SRAM heuristics for Mega Drive games
Todo:
- need to serialize the new cartridge ramEnable, ramWritable, bank
variables
¹: so technically, the GBA has its FIFO queue (raw PCM), plus a GB
chipset. The GB audio runs at 2MHz. However, I was being lazy and
running the sequencer 64 times in a row, thus decimating the audio to
32KHz. But simply discarding 63 out of every 64 samples resorts in
muddier sound with more static in it.
However ... increasing the audio thread processing intensity 64-fold,
and requiring heavy-duty three-chain lowpass and highpass filters is not
cheap. For this bump in sound quality, we're eating a loss of about 30%
of previous performance.
Also note that the GB audio emulation in the GBA core still lacks many
of the improvements made to the GB core. I was hoping to complete the GB
enhancements, but it seems like I'm never going to pass blargg's
psychotic edge case tests. So, first I want to clean up the GB audio to
my current coding standards, and then I'll port that over to the GBA,
which should further increase sound quality. At that point, it sound
exceed mGBA's audio quality (due to the ridiculously high sampling rate
and strong-attenuation audio filtering.)
²: word writes are probably not handled correctly ... but games are
only supposed to do byte writes here.
³: the SRAM mapping is used by games like "Story of Thor" and
"Phantasy Star IV." Unfortunately, the former wasn't released in the US
and is region protected. So you'll need to change the NTSU to NTSCJ in
md/system/system.cpp in order to boot it. But it does work nicely now.
The write protection bit is cleared in the game, and then it fails to
write to SRAM (soooooooo many games with SRAM write protection do this),
so for now I've had to disable checking that bit. Phantasy Star IV has a
US release, but sadly the game doesn't boot yet. Hitting some other bug.
The bank mapping is pretty much just for the 40mbit Super Street Fighter
game. It shows the Sega and Capcom logos now, but is hitting yet another
bug and deadlocking.
For now, I emulate the SRAM/bank mapping registers on all cartridges,
and set sane defaults. So long as games don't write to $a130XX, they
should all continue to work. But obviously, we need to get to a point
where higan/icarus can selectively enable these registers on a per-game
basis.
⁴: so, the Mega Drive has various ways to lock a chip until another
chip releases it. The VDP can lock the 68K, the 68K can lock the Z80,
etc. If this happens when you save a state, it'll dead-lock the
emulator. So that's obviously a problem that needs to be fixed. The fix
will be nasty ... basically, bypassing the dead-lock, creating a
miniature, one-instruction-long race condition. Extremely unlikely to
cause any issues in practice (it's only a little worse than the SNES
CPU/SMP desync), but ... there's nothing I can do about it. So you'll
have to take it or leave it. But yeah, for now, save states may lock up
the emulator. I need to add code to break the loops when in the process
of creating a save state still.
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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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Tim Allen
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4c3f9b93e7 |
Update to v102r12 release.
byuu says:
Changelog:
- MD/PSG: fixed 68K bus Z80 status read address location
- MS, GG, MD/PSG: channels post-decrement their counters, not
pre-decrement [Cydrak]¹
- MD/VDP: cache screen width registers once per scanline; screen
height registers once per frame
- MD/VDP: support 256-width display mode (used in Shining Force, etc)
- MD/YM2612: implemented timers²
- MD/YM2612: implemented 8-bit PCM DAC²
- 68000: TRAP instruction should index the vector location by 32 (eg
by 128 bytes), fixes Shining Force
- nall: updated hex(), octal(), binary() functions to take uintmax
instead of template<typename T> parameter³
¹: this one makes an incredible difference. Sie noticed that lots of
games set a period of 0, which would end up being a really long period
with pre-decrement. By fixing this, noise shows up in many more games,
and sounds way better in games even where it did before. You can hear
extra sound on Lunar - Sanposuru Gakuen's title screen, the noise in
Sonic The Hedgehog (Mega Drive) sounds better, etc.
²: this also really helps sound. The timers allow PSG music to play
back at the correct speed instead of playing back way too quickly. And
the PCM DAC lets you hear a lot of drum effects, as well as the
"Sega!!" sound at the start of Sonic the Hedgehog, and the infamous,
"Rise from your grave!" line from Altered Beast.
Still, most music on the Mega Drive comes from the FM channels, so
there's still not a whole lot to listen to.
I didn't implement Cydrak's $02c test register just yet. Sie wasn't 100%
certain on how the extended DAC bit worked, so I'd like to play it a
little conservative and get sound working, then I'll go back and add a
toggle or something to enable undocumented registers, that way we can
use that to detect any potential problems they might be causing.
³: unfortunately we lose support for using hex() on nall/arithmetic
types. If I have a const Pair& version of the function, then the
compiler gets confused on whether Natural<32> should use uintmax or
const Pair&, because compilers are stupid, and you can't have explicit
arguments in overloaded functions. So even though either function would
work, it just decides to error out instead >_>
This is actually really annoying, because I want hex() to be useful for
printing out nall/crypto keys and hashes directly.
But ... this change had to be made. Negative signed integers would crash
programs, and that was taking out my 68000 disassembler.
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Tim Allen
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1cab2dfeb8 |
Update to v102r11 release.
byuu says:
Changelog:
- MD: connected 32KB cartridge RAM up to every Genesis game under 2MB
loaded¹
- MS, GG, MD: improved PSG noise channel emulation, hopefully²
- MS, GG, MD: lowered PSG volume so that the lowpass doesn't clamp
samples³
- MD: added read/write handlers for VRAM, VSRAM, CRAM
- MD: block VRAM copy when CD4 is clear⁴
- MD: rewrote VRAM fill, VRAM copy to be byte-based⁵
- MD: VRAM fill byte set should fall through to regular data port
write handler⁶
¹: the header parsing for backup RAM is really weird. It's spaces
when not used, and seems to be 0x02000001-0x02003fff for the Shining
games. I don't understand why it starts at 0x02000001 instead of
0x02000000. So I'm just forcing every game to have 32KB of RAM for now.
There's also special handling for ROMs > 2MB that also have RAM
(Phantasy Star IV, etc) where there's a toggle to switch between ROM and
RAM. For now, that's not emulated.
I was hoping the Shining games would run after this, but they're still
dead-locking on me :(
²: Cydrak pointed out some flaws in my attempt to implement what he
had. I was having trouble understanding what he meant, so I went back
and read the docs on the sound chip and tried implementing the counter
the way the docs describe. Hopefully I have this right, but I don't know
of any good test ROMs to make sure my noise emulation is correct. The
docs say the shifted-out value goes to the output instead of the low bit
of the LFSR, so I made that change as well.
I think I hear the noise I'm supposed to in Sonic Marble Zone now, but
it seems like it's not correct in Green Hill Zone, adding a bit of an
annoying buzz to the background music. Maybe it sounds better with the
YM2612, but more likely, I still screwed something up :/
³: it's set to 50% range for both cores right now. For the MD, it
will need to be 25% once YM2612 emulation is in.
⁴: technically, this deadlocks the VDP until a hard reset. I could
emulate this, but for now I just don't do the VRAM copy in this case.
⁵: VSRAM fill and CRAM fill not supported in this new mode. They're
technically undocumented, and I don't have good notes on how they work.
I've been seeing conflicting notes on whether the VRAM fill buffer is
8-bits or 16-bits (I chose 8-bits), and on whether you write the low
byte and then high byte of each words, or the high byte and then low
byte (I chose the latter.)
The VRAM copy improvements fix the opening text in Langrisser II, so
that's great.
⁶: Langrisser II sets the transfer length to one less than needed to
fill the background letter tile on the scenario overview screen. After
moving to byte-sized transfers, a black pixel was getting stuck there.
So effectively, VRAM fill length becomes DMA length + 1, and the first
byte uses the data port so it writes a word value instead of just a byte
value. Hopefully this is all correct, although it probably gets way more
complicated with the VDP FIFO.
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Tim Allen
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8071da4c6a |
Update to v102r09 release.
byuu says:
Changelog:
- MD: restructured DMA to a subclass of VDP
- MD: implemented VRAM copy mode (fixes Langrisser II ... mostly)
- MS: implemened PSG support [Cydrak]
- GG: implemented PSG stereo sound support
- MS: use the new struct Model {} design that other cores use
The MS/GG PSG should be feature complete, but I don't have good tests
for Game Gear stereo mode, nor for the noise channel. There's also a
really weird behavior with when to reload the channel counters on volume
register writes. I can confirm what Cydrak observed in that following
the docs and reloading always creates serious audio distortion problems.
So, more research is needed there.
To get the correct sound out of the PSG, I have to run it at 3.58MHz /
16, which seems really weird to me. The docs make it sound like it's
supposed to run at the full 3.58MHz. If we can really run it at
223.7KHz, then that's help reduce the overhead of PSG emulation, which
will definitely come in handy for Mega Drive, and possibly later Mega
CD, emulation.
I have not implemented the PSG into the Mega Drive just yet. Nor have I
implemented save states or cheat code support into the MS/GG cores yet.
The latter is next on my list.
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Tim Allen
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7c96826eb0 |
Update to v101r13 release.
byuu says:
Changelog:
- MS: added ms/bus
- Z80: implemented JP/JR/CP/DI/IM/IN instructions
- MD/VDP: added window layer emulation
- MD/controller/gamepad: fixed d2,d3 bits (Altered Beast requires
this)
The Z80 is definitely a lot nastier than the LR35902. There's a lot of
table duplication with HL→IX→IY; and two of them nest two levels deep
(eg FD CB xx xx), so the design may change as I implement more.
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Tim Allen
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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.
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Tim Allen
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f7ddbfc462 |
Update to v101r11 release.
byuu says:
Changelog:
- 68K: fixed NEG/NEGX operand order
- 68K: fixed bug in disassembler that was breaking trace logging
- VDP: improved sprite rendering (still 100% broken)
- VDP: added horizontal/vertical scrolling (90% broken)
Forgot:
- 68K: fix extension word sign bit on indexed modes for disassembler
as well
- 68K: emulate STOP properly (use r.stop flag; clear on IRQs firing)
I'm really wearing out fast here. The Genesis documentation is somehow
even worse than Game Boy documentation, but this is a far more complex
system.
It's a massive time sink to sit here banging away at every possible
combination of how things could work, only to see no positive
improvements. Nothing I do seems to get sprites to do a goddamn thing.
squee says the sprite Y field is 10-bits, X field is 9-bits. genvdp says
they're both 10-bits. BlastEm treats them like they're both 10-bits,
then masks off the upper bit so it's effectively 9-bits anyway.
Nothing ever bothers to tell you whether the horizontal scroll values
are supposed to add or subtract from the current X position. Probably
the most basic detail you could imagine for explaining horizontal
scrolling and yet ... nope. Nothing.
I can't even begin to understand how the VDP FIFO functionality works,
or what the fuck is meant by "slots".
I'm completely at a loss as how how in the holy hell the 68K works with
8-bit accesses. I don't know whether I need byte/word handlers for every
device, or if I can just hook it right into the 68K core itself. This
one's probably the most major design detail. I need to know this before
I go and implement the PSG/YM2612/IO ports-\>gamepads/Z80/etc.
Trying to debug the 68K is murder because basically every game likes to
start with a 20,000,000-instruction reset phase of checksumming entire
games, and clearing out the memory as agonizingly slowly as humanly
possible. And like the ARM, there's too many registers so I'd need three
widescreen monitors to comfortably view the entire debugger output lines
onscreen.
I can't get any test ROMs to debug functionality outside of full games
because every **goddamned** test ROM coder thinks it's acceptable to tell
people to go fetch some toolchain from a link that died in the late '90s
and only works on MS-DOS 6.22 to build their fucking shit, because god
forbid you include a 32KiB assembled ROM image in your fucking archives.
... I may have to take a break for a while. We'll see.
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Tim Allen
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4d2e17f9c0 |
Update to v101r09 release.
byuu says:
Sorry, two WIPs in one day. Got excited and couldn't wait.
Changelog:
- ADDQ, SUBQ shouldn't update flags when targeting an address register
- ADDA should sign extend effective address reads
- JSR was pushing the PC too early
- some improvements to 8-bit register reads on the VDP (still needs
work)
- added H/V counter reads to the VDP IO port region
- icarus: added support for importing Master System and Game Gear ROMs
- tomoko: added library sub-menus for each manufacturer
- still need to sort Game Gear after Mega Drive somehow ...
The sub-menu system actually isn't all that bad. It is indeed a bit more
annoying, but not as annoying as I thought it was going to be. However,
it looks a hell of a lot nicer now.
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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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