byuu says:
Changelog:
- MS, MD, PCE: remove controllers from scheduler in destructor
[hex_usr]
- PCE: no controller should return all bits set (still causing errant
key presses when swapping gamepads)
- PCE: emulate MDR for hardware I/O $0800-$17ff
- PCE: change video resolution to 1140x242
- PCE: added tertiary background Vscroll register (secondary cache)
- PCE: create classes out of VDC VRAM, SATB, CRAM for cleaner access
and I/O registers
- PCE: high bits of CRAM read should be set
- PCE: partially emulated VCE display registers: color frequency, HDS,
HDW, VDS, VDW
- PCE: 32-width sprites now split to two 16-width sprites to handle
overflow properly
- PCE: hopefully emulated sprite zero hit correctly (it's not well
documented, and not often used)
- PCE: trigger line coincidence interrupts during the previous
scanline's Hblank period
- tomoko: raise viewport from 320x240 to 326x242 to accommodate PC
Engine's max resolution
- nall: workaround for Clang compilation bug that can't figure out
that a char is an integral data type
byuu says (in the public announcement):
This release adds very preliminary emulation of the Sega Master System
(Mark III), Sega Game Gear, Sega Mega Drive (Genesis), and NEC PC Engine
(Turbografx-16). These cores do not yet offer sound emulation, save
states or cheat codes.
I'm always very hesitant to release a new emulation core in its alpha
stages, as in the past this has resulted in lasting bad impressions
of cores that have since improved greatly. For instance, the Game Boy
Advance emulation offered today is easily the second most accurate around,
yet it is still widely judged by its much older alpha implementation.
However, it's always been tradition with higan to not hold onto code
in secret. Rather than delay future releases for another year or two,
I'll put my faith in you all to understand that the emulation of these
systems will improve over time.
I hope that by releasing things as they are now, I might be able to
receive some much needed assistance in improving these cores, as the
documentation for these new systems is very much less than ideal.
byuu says (in the WIP forum):
Changelog:
- PCE: latch background scroll registers (fixes Neutopia scrolling)
- PCE: clip background attribute table scrolling (fixes Blazing Lazers
scrolling)
- PCE: support background/sprite enable/disable bits
- PCE: fix large sprite indexing (fixes Blazing Lazers title screen
sprites)
- HuC6280: wrap zeropage accesses to never go beyond $20xx
- HuC6280: fix alternating addresses for block move instructions
(fixes Neutopia II)
- HuC6280: block move instructions save and restore A,X,Y registers
- HuC6280: emulate BCD mode (may not be 100% correct, based on SNES
BCD) (fixes Blazing Lazers scoring)
byuu says:
Changelog:
- PCE: added 384KB HuCard ROM mirroring mode
- PCE: corrected D-pad polling order
- PCE: corrected palette color ordering (GRB, not RGB -- yes,
seriously)
- PCE: corrected SATB DMA -- should write to SATB, not to VRAM
- PCE: broke out Background, Sprite VDC settings to separate
subclasses
- PCE: emulated VDC backgrounds
- PCE: emulated VDC sprites
- PCE: emulated VDC sprite overflow, collision interrupts
- HuC6280: fixed disassembler output for STi instructions
- HuC6280: added missing LastCycle check to interrupt()
- HuC6280: fixed BIT, CMP, CPX, CPY, TRB, TSB, TST flag testing and
result
- HuC6280: added extra cycle delays to the block move instructions
- HuC6280: fixed ordering for flag set/clear instructions (happens
after LastCycle check)
- HuC6280: removed extra cycle from immediate instructions
- HuC6280: fixed indirectLoad, indirectYStore absolute addressing
- HuC6280: fixed BBR, BBS zeropage value testing
- HuC6280: fixed stack push/pull direction
Neutopia looks okay until the main title screen, then there's some
gibberish on the bottom. The game also locks up with some gibberish once
you actually start a new game. So, still not playable just yet =(
byuu says:
Changelog:
- PCE: emulated gamepad polling
- PCE: emulated CPU interrupt sources
- PCE: emulated timer
- PCE: smarter emulation of ST0,ST1,ST2 instructions
- PCE: better structuring of CPU, VDP IO registers
- PCE: connected palette generation to the interface
- PCE: emulated basic VDC timing
- PCE: emulated VDC Vblank, Coincidence, and DMA completion IRQs
- PCE: emulated VRAM, SATB DMA transfers
- PCE: emulated VDC I/O registers
Everything I've implemented today likely has lots of bugs, and is
untested for obvious reasons.
So basically, after I fix many horrendous bugs, it should now be
possible to implement the VDC and start getting graphical output.
byuu says:
Changelog:
- PCE: HuC6280 core completed
There's bound to be a countless stream of bugs, and the cycle counts are
almost certainly not exact yet, but ... all instructions are implemented.
So at this point, I can start comparing trace logs against Mednafen's
debugger output.
Of course, we're very likely to immediately slam into a wall of needing
I/O registers implemented for the VDC in order to proceed further.
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: added cartridge ROM/RAM mirroring (fixes Alex Kidd)
- SMS: fixed 8x16 sprite mode (fixes Wonder Boy, Ys graphics)
- Z80: emulated "ex (sp),hl" instruction
- Z80: fixed INx NF (should be set instead of cleared)
- Z80: fixed loop condition check for CPxR, INxR, LDxR, OTxR (fixes
walking in Wonder Boy)
- SFC: removed Debugger and sfc/debugger.hpp
- icarus: connected MS, GG, MD importing to the scan dialog
- PCE: added emulation skeleton to higan and icarus
At this point, Master System games are fairly highly compatible, sans
audio. Game Gear games are running, but I need to crop the resolution
and support the higher color palette that they can utilize. It's really
something else the way they handled the resolution shrink on that thing.
The last change is obviously going to be the biggest news.
I'm very well aware it's not an ideal time to start on a new emulation
core, with the MS and MD cores only just now coming to life with no
audio support.
But, for whatever reason, my heart's really set on working on the PC
Engine. I wanted to write the final higan skeleton core, and get things
ready so that whenever I'm in the mood to work on the PCE, I can do so.
The skeleton is far and away the most tedious and obnoxious part of the
emulator development, because it's basically all just lots of
boilerplate templated code, lots of new files to create, etc.
I really don't know how things are going to proceed ... but I can say
with 99.9% certainty that this will be the final brand new core ever
added to higan -- at least one written by me, that is. This was
basically the last system from my childhood that I ever cared about.
It's the last 2D system with games that I really enjoy playing. No other
system is worth dividing my efforts and reducing the quality and amount
of time to work on the systems I have.
In the future, there will be potential for FDS, Mega CD and PCE-CD
support. But those will all be add-ons, and they'll all be really
difficult and challenge the entire design of higan's UI (it's entirely
cartridge-driven at this time.) None of them will be entirely new cores
like this one.
Tim Allen