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
byuu says (in the WIP forum):
Changelog:
- higan: cheat codes accept = and ? separators now
- the new preferred code format is: address=value or
address=if-match?value
- the old code format of address/value and address/if-match/value
will continue to work
- higan: cheats.bml is no longer included with the base distribution
- mightymo stopped updating it in 2015, and it's not source code;
it can still be pulled in from older releases
- fc: improved PAL mode timing; use PAL APU timing tables; fix PAL
noise period table [hex\_usr]
- md: support aborting a Z80 bus wait in order to capture save states
without freezing
- note that this will violate accuracy; but in practice a slight
desync is better than an emulator deadlock
- sfc: revert DSP ENDX randomization for now (want to research it more
before deploying in an official release)
- sfc: fix Super Famicom.sys/manifest.bml APU RAM size [hex\_usr]
- tomoko: cleaned up make install rules
- hiro/cocoa: use ABGR for pixel data [Sintendo]
Note: I forgot to change the command-line and drag-and-drop separator
from : to | in this WIP. However, it is corrected in the v103 official
binary and source published on download.byuu.org. Sorry about that, I
know it makes the Git repository history more difficult. I'm not
concerned whether the : → | change is part of v103 or v103r01 in the
repository, and will leave this to your discretion, Screwtape.
I also still need to set the VDP bit to indicate PAL mode in the Mega
Drive core. This is what happens when I have 47 things I have to do,
given how lousy my memory is. I miss things.
byuu says:
Changelog:
- removed Emulator::Interface::Capabilities¹
- MS: improved the PSG emulation a bit
- MS: added cheat code support
- MS: added save state support²
- MD: emulated the PSG³
¹: there's really no point to it anymore. I intend to add cheat codes
to the GBA core, as well as both cheat codes and save states to the Mega
Drive core. I no longer intend to emulate any new systems, so these
values will always be true. Further, the GUI doesn't respond to these
values to disable those features anymore ever since the hiro rewrite, so
they're double useless.
²: right now, the Z80 core is using a pointer for HL-\>(IX,IY)
overrides. But I can't reliably serialize pointers, so I need to convert
the Z80 core to use an integer here. The save states still appear to
work fine, but there's the potential for an instruction to execute
incorrectly if you're incredibly unlucky, so this needs to be fixed as
soon as possible. Further, I still need a way to serialize
array<T, Size> objects, and I should also add nall::Boolean
serialization support.
³: I don't have a system in place to share identical sound chips. But
this chip is so incredibly simple that it's not really much trouble to
duplicate it. Further, I can strip out the stereo sound support code
from the Game Gear portion, so it's even tinier.
Note that the Mega Drive only just barely uses the PSG. Not at all in
Altered Beast, and only for a tiny part of the BGM music on Sonic 1,
plus his jump sound effect.
byuu says:
Changelog:
- SMS: fixed controller connection bug
- SMS: fixed Z80 reset bug
- PCE: emulated HuC6280 MMU
- PCE: emulated HuC6280 RAM
- PCE: emulated HuCard ROM reading
- PCE: implemented 178 instructions
- tomoko: removed "soft reset" functionality
- tomoko: moved "power cycle" to just above "unload" option
I'm not sure of the exact number of HuC6280 instructions, but it's less
than 260.
Many of the ones I skipped are HuC6280-originals that I don't know how
to emulate just yet.
I'm also really unsure about the zero page stuff. I believe we should be
adding 0x2000 to the addresses to hit page 1, which is supposed to be
mapped to the zero page (RAM). But when I look at turboEMU's source, I
have no clue how the hell it could possibly be doing that. It looks to
be reading from page 0, which is almost always ROM, which would be ...
really weird.
I also don't know if I've emulated the T mode opcodes correctly or not.
The documentation on them is really confusing.
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.
byuu says:
Changelog:
- SMS: emulated the remaining 240 instructions in the (0xfd, 0xdd)
0xcb (displacement) (opcode) set
- 1/8th of these were "legal" instructions, and apparently games
use them a lot
- SMS: emulated the standard gamepad controllers
- reset button not emulated yet
The reset button is tricky. In every other case, reset is a hardware
thing that instantly reboots the entire machine.
But on the SMS, it's more like a gamepad button that's attached to the
front of the device. When you press it, it fires off a reset vector
interrupt and the gamepad polling routine lets you query the status of
the button.
Just having a reset option in the "Master System" hardware menu is not
sufficient to fully emulate the behavior. Even more annoying is that the
Game Gear doesn't have such a button, yet the core information structs
aren't flexible enough for the Master System to have it, and the Game
Gear to not have it, in the main menu. But that doesn't matter anyway,
since it won't work having it in the menu for the Master System.
So as a result, I'm going to have to have a new "input device" called
"Hardware" that has the "Reset" button listed under there. And for the
sake of consistency, I'm not sure if we should treat the other systems
the same way or not :/
byuu says:
Changelog:
- Makefile: added $(windres), -lpthread to Windows port
- GBA: WAITCNT.prefetch is not writable (should fix Donkey Kong: King
of Swing) \[endrift\]
- SMS: fixed hcounter shift value \[hex\_usr\]
- SMS: emulated interrupts (reset button isn't hooked up anywhere, not
sure where to put it yet)
This WIP actually took a really long time because the documentation on
SMS interrupts was all over the place. I'm hoping I've emulated them
correctly, but I honestly have no idea. It's based off my best
understanding from four or five different sources. So it's probably
quite buggy.
However, a few interrupts fire in Sonic the Hedgehog, so that's
something to start with. Now I just have to hope I've gotten some games
far enough in that I can start seeing some data in the VDP VRAM. I need
that before I can start emulating graphics mode 4 to get some actual
screen output.
Or I can just say to hell with it and use a "Hello World" test ROM.
That'd probably be smarter.
byuu says:
Changelog:
- SMS: extended bus mapping of in/out ports: now decoding them fully
inside ms/bus
- SMS: moved Z80 disassembly code from processor/z80 to ms/cpu
(cosmetic)
- SMS: hooked up non-functional silent PSG sample generation, so I can
cap the framerate at 60fps
- SMS: hooked up the VDP main loop: 684 clocks/scanline, 262
scanlines/frame (no PAL support yet)
- SMS: emulated the VDP Vcounter and Hcounter polling ... hopefully
it's right, as it's very bizarre
- SMS: emulated VDP in/out ports (data read, data write, status read,
control write, register write)
- SMS: decoding and caching all VDP register flags (variable names
will probably change)
- nall: \#undef IN on Windows port (prevent compilation warning on
processor/z80)
Watching Sonic the Hedgehog, I can definitely see some VDP register
writes going through, which is a good sign.
Probably the big thing that's needed before I can get enough into the
VDP to start showing graphics is interrupt support. And interrupts are
never fun to figure out :/
What really sucks on this front is I'm flying blind on the Z80 CPU core.
Without a working VDP, I can't run any Z80 test ROMs to look for CPU
bugs. And the CPU is certainly too buggy still to run said test ROM
anyway. I can't find any SMS emulators with trace logging from reset.
Such logs vastly accelerate tracking down CPU logic bugs, so without
them, it's going to take a lot longer.
byuu says:
Changelog:
- rewrote the Z80 core to properly handle 0xDD (IX0 and 0xFD (IY)
prefixes
- added Processor::Z80::Bus as a new type of abstraction
- all of the instructions implemented have their proper T-cycle counts
now
- added nall/certificates for my public keys
The goal of `Processor::Z80::Bus` is to simulate the opcode fetches being
2-read + 2-wait states; operand+regular reads/writes being 3-read. For
now, this puts the cycle counts inside the CPU core. At the moment, I
can't think of any CPU core where this wouldn't be appropriate. But it's
certainly possible that such a case exists. So this may not be the
perfect solution.
The reason for having it be a subclass of Processor::Z80 instead of
virtual functions for the MasterSystem::CPU core to define is due to
naming conflicts. I wanted the core to say `in(addr)` and have it take
the four clocks. But I also wanted a version of the function that didn't
consume time when called. One way to do that would be for the core to
call `Z80::in(addr)`, which then calls the regular `in(addr)` that goes to
`MasterSystem::CPU::in(addr)`. But I don't want to put the `Z80::`
prefix on all of the opcodes. Very easy to forget it, and then end up not
consuming any time. Another is to use uglier names in the
`MasterSystem::CPU` core, like `read_`, `write_`, `in_`, `out_`, etc. But,
yuck.
So ... yeah, this is an experiment. We'll see how it goes.
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.
byuu says:
Changelog:
- 68K: MOVEQ is 8-bit signed
- 68K: disassembler was print EOR for OR instructions
- 68K: address/program-counter indexed mode had the signed-word/long
bit backward
- 68K: ADDQ/SUBQ #n,aN always works in long mode; regardless of size
- 68K→VDP DMA needs to use `mode.bit(0)<<22|dmaSource`; increment by
one instead of two
- Z80: added registers and initial two instructions
- MS: hooked up enough to load and start running games
- Sonic the Hedgehog can execute exactly one instruction... whoo.
Tim Allen