EmuNations

Most Recent Changes

--0.11.0--

Some of the most notable changes since v0.10:

• Game Boy Advance emulation now supported

• 32X now supports emulated CPU overclocking

• Slightly improved 32X color accuracy

• Improved 32X PWM audio quality

• Sega CD per-region BIOS configuration

• NES palette customization options

• Game Boy and Game Boy Color now support LCD ghosting emulation via frame blending

• Support for running original Game Boy games in Game Boy Color mode

• Support for turbo/autofire input mappings

• Fixed a ton of bugs for every system, including two Sega CD regressions that affected v0.10

• SDL upgraded from SDL2 to SDL3

Save states are not compatible with previous versions.

I did not intend for this to come so long after the last release, but there was always just one more thing...

Game Boy Advance

• Game Boy Advance emulation is now supported; requires a Game Boy Advance BIOS ROM

• Video options for color correction and LCD ghosting emulation (frame blending), both enabled by default

• Audio enhancement option to apply enhanced interpolation to the Direct Sound channels rather than accurately emulating actual hardware's resampling behaviorThis massively reduces audio aliasing and noise in most cases, but it can also make audio sound muffled when games use very low sample rates (as most GBA games do)

• CPU/prefetch/DMA/etc. timing is not perfect but should be moderately accurate

• All types of cartridge save memory supported, with an option to force a specific type if auto-detection gets it wrong

• The cartridge RTC chip and solar sensor are emulated for the handful of games that use them (e.g. Boktai), other cartridge peripherals are not currently emulated

New Features

• (Genesis) Added an option to ignore configured aspect ratio and display square pixels when the VDP is in H40/H320px mode (#442)

• (Genesis) Added support for games with 24C64 EEPROM chips; College Slam and Frank Thomas Big Hurt Baseball are now playable (#459)

• (Genesis) New audio option to enable/disable individual YM2612 audio channels

• (Genesis) New audio option to adjust volume of individual sound sources

• (Genesis) Added some additional memory/register views to the Memory Viewer window

• (Sega CD) Added support for per-region BIOS configuration, where the emulator will automatically select the appropriate BIOS based on game region

• (32X) Added two new color display options (#492)New option to darken Genesis colors relative to 32X colors, enabled by default; on actual hardware the brightest 32X colors are noticeably brighter than the brightest Genesis colors
  New option to apply a yellow or purple tint to 32X colors, roughly as observed on actual hardware

• (32X) Added an option to overclock the SH-2s; this is extremely CPU-intensive but can reduce slowdown in some games

• (32X) Added options to hide all pixels of a given priority (#494)

• (NES) Added palette customization options (#424)Can now load a custom palette from a file; both 64-color and full 512-color palette files supported
  GUI now has a builtin NTSC palette generator with a graphic displaying the current palette

• (SNES) Added support for the ST018 coprocessor, used by Hayazashi Nidan Morita Shougi 2This is emulated using an ARM7TDMI implementation (ARMv4T) rather than an ARM6 (ARMv3), but this should not make any functional difference

• (GB) Added a frame blending option that simulates LCD ghosting, enabled by default; enabling this fixes graphical effects in a few games and demos (#469)

• (GB) When color correction is enabled, you can now manually adjust the LCD gamma value used for gamma correction

• (GB) Added support for booting from a boot ROM (#404)

• (GB) Added an option to run original Game Boy software in Game Boy Color mode (#150)This feature requires a GBC boot ROM in order to initialize the compatibility palettes, and it is off by default because it (accurately) causes major bugs in a few games

• (GB) Added (proper) support for the MBC30 mapper, used by the Japanese version of Pocket Monsters Crystal Version (#478)

• (GB) Added support for unlicensed/homebrew games with an SRAM size byte of $01 (2 KB) (#485)

• (Game Gear) Added a frame blending option that simulates LCD ghosting, currently disabled by default

• (Game Gear) Added support for booting from a BIOS / boot ROM (#404)

• Added turbo button support for face and shoulder buttons on all emulated systems (#554)

• Added options to automatically pause the emulator when in the background (#585)

Improvements

• Upgraded SDL from SDL2 to SDL3; for the most part this should hopefully have no noticeable impact except for audio playback maybe working a little better than beforeAs part of this, I removed the borderless vs. exclusive fullscreen setting because this seemed much less straightforward to change in SDL3; fullscreen will now always use whatever the platform and graphics driver default to (probably always borderless on modern platforms)

• The auto-prescale video setting can now use separate scale factors for width and height, which produces a less aliased image when games use display modes with sub-1 pixel aspect ratio (e.g. Genesis NTSC H40/H320px mode, SNES high-res modes)Auto-prescale is also now enabled by default (the previous default was a fixed 3x upscale factor)

• (32X) Improved quality of PWM chip audio resamplingThere is also a new audio option to switch to the old resampling algorithm, which is lower quality but usually sounds a little sharper (given that most 32X games use PWM sample rates of 22 KHz or less)

• (SNES) When using the Super Scope, the emulator now displays the new Super Scope Turbo state whenever you toggle Turbo on/off

• (GB) Audio is now sampled internally at 2 MHz rather than 1 MHz, which should reduce audio aliasing from the wavetable channel

General Fixes

• Fixed a number of cases that would cause the emulator to crash, none triggered by official releases (as far as I know) but some triggered by homebrew/demos/test ROMs(Genesis) Loading a ROM file smaller than 1 KB or so (#434)
  (Genesis) Z80 tries to access its own memory through the 32KB 68K memory bank by mapping it to $A00000-$A07FFF or $A08000-$A0FFFF
  (Genesis) VRAM-to-VRAM copy DMA with source address higher than $1FFFF
  (Genesis) 68000 triggers a privilege violation exception
  (Genesis) 68000 triggers an address error while handling an exception
  (32X) One of the SH-2s executes a SLEEP instruction (#431)
  (32X) One of the SH-2s executes an illegal opcode
  (32X) One of the SH-2s tries to access certain invalid memory addresses (highest 3 bits set to 100 or 101)
  (32X) 68000 performs a 16-bit read from certain invalid memory addresses
  (SMS / Game Gear / Genesis) Z80 handles an IRQ while in interrupt mode 2
  (SNES) Loading a ROM file smaller than 32 KB (#538)
  (SNES) Loading an SA-1 cartridge where the cartridge header claims it does not have any BW-RAM (anything that does this now gets 64 KB of BW-RAM)
  (SNES) SA-1 Character Conversion DMA Type 1 with an I-RAM destination address higher than $7FF
  (GB) CPU executes a STOP instruction with no CGB speed switch armed (#465)

• Fixed changes to the save path and save state path options not applying immediately if changed while an emulator is running

• Fixed the UI theme option not applying to the Memory Viewer window

Genesis / Sega CD / 32X Fixes

• Fixed the VDP rendering too many pixels of the previous color when a game makes a mid-scanline backdrop color change while display is disabled; this improves accuracy of the glitchy lines in Gouketsuji Ichizoku / Power Instinct (#462)

• Fixed the 6-button controller timeout period being a little too short (#445)

• Fixed two games failing to boot due to the emulator not giving them the correct type of cartridge save memoryHonoo no Toukyuuji: Dodge Danpei has a 24C01 EEPROM chip (#460)
  Al Michaels Announces HardBall III has 32 KB of SRAM (#546)

• Slightly adjusted memory refresh delay timing when the main CPU is executing out of RAM; this fixes incorrectly visible CRAM dots in Snatcher

• (Sega CD) Fixed implementation of VDP DMA reads from word RAM being delayed; this fixes glitchy background graphics in Snatcher (again)This was a regression that affected v0.10.0 and v0.10.1; it was broken by VDP DMA changes in v0.10.0

• (Sega CD / 32X) Adjusted inter-CPU/VDP timings to account for some VDP timing changes made in v0.10.0; this fixes the Sega CD version of Mickey Mania having glitchy graphics on the right side of the screen in the 3D chase stages (#491)This was also a regression that affected v0.10.0 and v0.10.1

• (32X) Improved accuracy of VDP auto fill timing; this fixes occasional major graphical glitches in Shadow Squadron / Stellar Assault during the intro and takeoff sequences (#225 / #439)

• (32X) Fixed some inaccuracies around VDP register latching; this fixes some early 32X demos not working properly (#430)

• (32X) Fixed some PWM resampling bugs that sometimes caused erroneous pops in PWM audio output

• (32X) Slightly improved SH-2 timing accuracy, particularly around 32-bit SDRAM writes being way too slow (#493)

• (32X) Fixed 32X HINT counter behavior not matching Genesis HINT behavior, which caused SH-2 horizontal interrupts to be off by a line (#559)

• (32X) Fixed 32X VDP per-line events (HBlank, line render) triggering slightly too early in the line

• Several timing fixes that fix graphical bugs in the Chaekopon demo by Limp Ninja (#435)Adjusted low-level sprite processing timings so that sprite attribute fetching is performed slightly earlier in the line
  Fixed a pretty egregious DMA timing bug where DMA would take way too long to start copying if initiated during active display with display enabled

• Fixed a number of inaccuracies identified by the testpico test ROM (#482)Fixed implementation of how Genesis VINT and HINT are delayed by 1 instruction when re-enabled; the previous implementation did the wrong thing when two consecutive MOVE instructions enabled then disabled VDP interrupts
  Fixed the Genesis VDP's F flag starting to read 1 (VINT pending) slightly later than it's supposed to
  (32X) Fixed behaviors related to enabling/disabling/clearing SH-2 VINT during VBlank
  (32X) Fixed some register bits being incorrectly writable / not writable
  (32X) Updates to initial state at power-on to more closely match actual hardware
  

NES Fixes

• Very slightly adjusted sprite 0 hit timing; this fixes glitchy lines on the title screen of Indiana Jones and the Last Crusade (#314)

• DMC DMA timing is now emulated; this fixes screen jitter in Ultimate Air Combat (#268)

• Fixed non-power-of-two CHR ROM sizes not working correctly (#573)

• Several fixes for inaccuracies identified by the AccuracyCoin test ROM (#551)Fixed an APU timing issue that sometimes caused an incorrectly skipped frame counter clock when software wrote 0x80 to $4017 with two consecutive sta $4017 instructions
  More accurate APU frame counter timing
  More accurate OAM DMA timing
  DMA dummy reads are now emulated (with a new option to disable dummy controller port reads because they cause input glitches in some games)
  CPU open bus is now properly emulated (it was previously faked by always returning the address high byte)
  More accurate PPU open bus emulation
  Most PPU registers are no longer writable immediately after reset
  Fixed the 6502 incorrectly polling the interrupt lines during the final cycle of BRK instructions and IRQ handling
  More accurate controller port behaviors around strobing and consecutive-cycle reads
  

SNES Fixes

• Fixed BG2 incorrectly not rendering in Mode 7 if BG1 is disabled and BG2+EXTBG are enabled; this fixes missing background graphics in F-1 Grand Prix (#529)

• Fixed V IRQs incorrectly not triggering when a game either 1. changes VTIME to the current line while V IRQs are enabled, or 2. enables V IRQs while VTIME is set to the current line; this fixes graphical corruption in F-1 Grand Prix, F-1 Grand Prix Part III, S.O.S.: Sink or Swim, and RoboCop vs. The Terminator (#529 / #530 / #543)

• Fixed multiple bugs in the BG vertical mosaic implementation, which was previously quite wrong; this fixes graphical bugs in Beavis and Butt-Head and Jurassic Park Part 2: The Chaos Continues (#532 / #540)

• Improved DMA timing accuracy; this fixes graphical glitches in Circuit USA (#531)

• Fixed incorrect DSP-1 port address mapping for DSP-1 cartridges with more than 1 MB of ROM; this fixes Super Bases Loaded 2 failing to boot (#534)

• Fixed some revisions of Tintin in Tibet incorrectly defaulting to NTSC timings instead of PAL (#539)

• The 65816 stack pointer is now initialized to $01FF instead of $0100; this fixes some homebrew games failing to boot due to stack corruption (#468)

• Fixed SA-1 Character Conversion DMA Type 1 in 2bpp or 4bpp mode incorrectly treating the input packed pixel data as big-endian within a byte when it is actually little-endian; this fixes graphical glitches in the SA-1 tech demo cartridge (#537)

• Implemented multiplication/division timing; this fixes some old homebrew that accidentally depends on reading intermediate division results (#576)

Game Boy [Color] Fixes

• Fixed the GBC color correction implementation nonsensically performing calculations in sRGB color space rather than linear color space; this makes a particularly huge difference for the GBA LCD option

• Slightly adjusted timing of when the STAT LY=LYC bit reads 1; this fixes a glitchy line in Elevator Action (#472)

• The serial port transfer data register (SB / $FF01) is now read/write; this fixes Card Game not allowing you to start the game (#471)

• Fixed sample output behavior of pulse and wavetable channels when the DAC is enabled but the channel is inactive

• Added approximate emulation of DAC fading when a channel's DAC is turned on or off; combined with the above change, this fixes buzzing noises in Cannon Fodder, 3D Pocket Pool, and others (#475)

• Fixed VRAM DMA incorrectly terminating prematurely when the destination address increments from $9FFF to $A000; this fixes freezing in F1 Championship Season 2000 (#464)

• HDMA5 writes with bit 7 set are now allowed to change the length of in-progress HDMAs; this fixes corrupted graphics in NASCAR 2000 (#467)

• HDMA is now able to halt the CPU mid-instruction; this fixes occasional glitchy frames in Toy Story Racer