byuu says:
Changelog:
- fc/apu: $4003,$4007 writes initialize duty counter to 0 instead of 7
- fc/apu: corrected duty table entries for use with decrementing duty
counter
- processor/spc700: emulated the behavior of cycle 3 of (x)+
instructions to not read I/O registers
- specifically, this prevents reads from $fd-ff from resetting the
timers, as observed on real hardware
- sfc/controller: added ControllerPort class to match Mega Drive
design
- sfc/expansion: added ExpansionPort class to match Mega Drive design
- sfc/system: removed Peripherals class
- sfc/system: changed `colorburst()` to `cpuFrequency()`; added
`apuFrequency()`
- sfc: replaced calls to `system.region == System::Region::*` with
`Region::*()`
- sfc/expansion: remove thread from scheduler when device is destroyed
- sfc/smp: `{read,write}Port` now use a separate 4x8-bit buffer instead
of underlying APU RAM [hex\_usr]
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.
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:
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