BlastEm Changelog

1.0.0

Released September 11th, 2026 - Announcement Post

Newly Supported Hardware

• Sega/Mega CD
• Sega 32X
• Sega Pico
• Yamaha Copera (OPL3 emulation missing, but all known games are playable)
• Game Gear
• SC-3000/SG-1000
• Colecovision
• Hearbeat Personal Trainer peripheral (needed for Outback Joey and other HPBT games)
• Sega Multitap

Quality of Life Improvements

• Nuklear UI now works even if OpenGL is disabled/unavailable
• Nuklear UI can now be navigated by keyboard or game controller
• Controller type and SDL2 mapping can now be changed after initial configuration
• Controllers are now ordered based on which one receives input first
• Implemented DPI scaling
• Added multiple new shaders, including some 3rd party contributions
• Added option to use system file picker on Windows and Linux (GTK only for the latter)
• Added support for Unicode and long paths on Windows
• Some 6-button style controllers now have correct mappings out of the box
• New option to save config files in the application folder for "portable" setups

New Features

• Genesis/Mega Drive model selection: Enables emulation of model-specific hardware quirks
• VGM logging
• Oscilloscope View
• New media player mode that can play VGM files along with WAVE and FLAC files
• "Video" recording (APNG + WAVE)

Debugging Improvements

• Completely reworked the CPU debuggers with a turing complete scripting language
• Added watchpoints for both 68K memory and VDP registers/RAM
• Enhanced palette viewer
• Enhanced VDP plane viewer
• Implemented KMod logging extensions

Accuracy Improvements

• Separated comopsiting from final output. Fixes minor glitch in the DF Retro Direct Color DMA demo
• Reworked sprite rendering phase 3 to better match documentation by Kabuto/TiTan. Fixes Alex Kidd minigame
• Fixed reading version reg from Z80 and open bus reads from VDP test reg
• Fixed YM2612 busy flag timing
• Fixed a Z80 interrupt edge case which broke the music in Metal Blast 2277
• Improved open bus emulation
• Fixed some edge cases in VDP address/command register updates. Fixes the Mona in 344 bytes demo.
• Fixed timing of a number of 68K instructions
• Fixed YM2612 Timer B load behavior that caused slow music playback in the Konami driver
• Implemented VDP read latency and invalid write delays
• Fixed YM2612 key scaling in CH3 special mode. Fixes sound effects in Toy Story and Maui Mallard
• Fixed VDP rendering behavior when all planes are disabled via the VDP test register
• Implemented additional YM2612 pan "leakage" present on real hardware
• Implemented undocumented Z80/PSG clock speed bit in VDP test registers
• Fixed handling of auto-release in SSG-EG without HOLD. Fixes whistle sound effect in Strikers

Bugfixes

• Fixed crash when pressing escape with no ROM loaded
• Fixed immediate cancel in keybinding view when mouse was positioned where cancel button appears
• Fixed crash when changing video screen settings when in full-screen
• Fixed crash when loading save states in games with the "SRAM" variant of the Sega mapper
• Fixed crash when repeatedly reloading a ROM or a sequence of different ROMs
• Fixed a bug in the implementation of the 'in (c)' Z80 instruction
• Fixed crash when loading new ROM via drag & drop when existing ROM has lock-on
• Fixed a number of bugs in the controller mapping UI

Other Changes

• Added a 64-bit Windows build
• Added new 68K and Z80 interpreters for building on non-x86/x86-64 targets
• Added an experimental web build
• Added ROM DB entries for a number of games that needed them
• Some very early work on LaserActive that emulates some parts of the PAC-less base player

0.6.2

Released March 28th, 2019

New Features

• Zipped and gzipped SMD ROMs are now supported
• Gain control for overall volume and FM/PSG invidually

Accuracy/Completeness Improvements

• Fixed timing of a few instructions in Z80 core
• Added optional emulation of YM2612 imperfections (aka "ladder effect")
• Fixed some unintentional extra precision in some FM LFO calculations
• Added a 1 sample delay in some FM operator results when used as modulators to match hardware

Bugfixes

• Fixed regression in NBA JAM TE and possibly other 32MBit Acclaim mapper titles
• Added code to handle controllers that have their d-pads mapped as buttons or axes
• Removed some problematic SDL2 game controller mappings
• Fixed crash that occurred when releasing mouse too clickly when loading a ROM
• Fixed SMD ROM support
• Fixed handling of audio contexts with more or less than 2 channels
• Fixed off-by-one error in IO device selection UI
• Fixed regression in GDB remote debugging support on Linux and OS X

Other Changes

• MegaWiFi hardware can now be enabled by a header string (still gated by config)
• Tweaked the style of checkboxes in the Nuklear UI to hopefully make the on/off state more clear

0.6.1

Released January 4th, 2019

Bugfixes

• Fixed build script so controller images are actually included so UI doesn't crash
• Disabled most bindings when UI active (fixes crashes/wonkiness when pressing certain keys)
• Fixed Windows implementation of get_config_dir() so config file ends up in %localappdata%\blastem like it should
• Fixed the location of sticky_path on all platforms
• Added virtual root directory used by ROM UI to new Nuklear UI

0.6.0

Released December 31st, 2018

New Features

• New Nuklear UI with almost complete access to configuration options
• Added support for creating SDL2 mappings from inside the emulator
• Loading ROMs from ZIP archives is now supported
• Loading gzip compressed ROMs is now supported
• Internal screenshots can now be in PNG format
• New VDP plane debug view
• VDP debug views are now in separate windows
• Experimental support for sync to video (not enabled by default)
• Preliminary support for MegaWifi cart emulation

Bugfixes

• Fixed a number of 68K decoder bugs (mostly illegal instruction decoding)
• Fixed implementation of the UNLK instruction when register is a7
• Fixed a number of memory leaks

Accuracy/Completeness Improvements

• Added support for J-Cart emulation
• Implemented Z80 interrupt mode 2
• Fixed the timing of a number of 68K instructions
• Fixed the timing of the Z80 JP cc, nn instruction
• Fixed the order bytes of a word are written to VRAM from the FIFO (fixes minor corruption in Road Rash 3 bike menu)

Other Changes

• Added support for Open GL ES in addition to the existing desktop GL support
• Some small optimizations
• Added ROM DB entry for Squirrel King to support it's copy protection
• Added support for float32 audio output (fixes an issue with defautl SDL2 driver in Windows when using more recent SDL2 versions)

0.5.1

Released August 30th, 2017

New Features

• Drag and Drop is now supported for loading ROMs
• Save states are now supported for SMS games
• Texture scaling method (linear or nearest neighbor) can now be selected in both renderers
• Menu now filters files based on a configurable extension list
• Lock on carts (Sonic & Knuckles and XBAND) can now be loaded via the menu
• ROMs can be reloaded via a hotkey (defaults to F5)
• Last path visited in the menu is now saved between runs (can be turned off via config)
• Window height can now be specified in the config file

Bugfixes

• Default shader doesn't look like garbage in interlaced mode anymore
• Framebuffer pointers are properly released and reacquired on context switch (no more LOCKRECT errors)
• ROMs specifying SRAM at the normal RAM address no longer cause a crash
• Fixed an edge case in the s(tep) debugger command
• Entering the option menu in Dragon's Fury no longer results in a fatal error in 32-bit builds
• Screen is properly cleared so garbage will not appear when the window does not match the emulated display size
• Fixed a regression in XBAND keyboard support

Accuracy/Completeness Improvements

• Locking on Sonic 3 to S&K will now use Sonic 3's save RAM
• Locking on a 4MB cart to S&K will now behave like on hardware
• Support for several X-in-1 bootleg carts has been added
• DMA from byte-wide SRAM now yields correct results
• VScroll is now latched earlier in the line (fixes minor glithces in Top Gear 2 and Skitchin)
• Sega/SSF2 mapper support now handles homebrew that uses SRAM
• ODD flag timing now matches hardware
• V counter as read from HV port is now correct in single-resolution interlace mode

Other Changes

• Added a "subtle" CRT shader contributed by Anaël Seghezzi
• Mouse is now only captured if an emulated mouse is plugged in to the emulated system
• Missing mapping warnings will only be displayed for the first mapping of a controller
• Save states now default to a format native to BlastEm
• Remaining I2C EEPROM games have been added to the ROM DB
• When not specified, height now respects the aspect setting rather than assuming 4:3
• Pre-combined S&K ROMs and large (>2MB) S&K hacks should now work
• Using ui.exit (default Escape) can now be used to cleanly cancel a load ROM or savestate action
• Save states are now allowed in a more extensive range of Z80 states, fixing save state saving in some games

0.5.0

Released June 2nd, 2017

New Features

• SMS emulation in the form of the Gensis/MD's backwards compatibility mode
• Added support for SMS controllers
• Support for the mapper used by Realtec games
• Support for carts with fixed value registers
• Support for enough of the XBAND cartridge hardware to allow the menu to boot
• Basic XBAND keyboard emulation
• Configurable display overscan
• Fullscreen mode can now be toggled at runtime
• Window can now be resized at runtime
• Support for "semantic" controller button names in the gamepad mapping using SDL2's game controller API
• Analog axes can now be mapped to emulated gamepad buttons or UI actions
• System soft reset
• Keyboard can now be captured when a Saturn or XBAND keyboard is connected to the emulated system
• Internal screenshots that bypass all output filtering/overscan
• Homebrew using the "SSF2 Mapper" is now supported via header detection like on the Mega Everdrive
• Directory used for SRAM, EEPROM and savestates is now configurable
• Path configuration values can now contain both BlastEm-specific and environment variable references
• Open GL based rendering can be disabled in favor of the SDL2 render API fallback

Bugfixes

• Fixed a bug that would cause a crash in certain games that have SRAM and ROM at the same address
• Fixed some issues with Z80 interrupts that caused issues with sound/music in Sonic 2 and Puyo Puyo 2
• Z80 debugger no longer crashes when resuming execution
• Undocumented Z80 instruction "out (c), 0" now decodes properly
• GDB remote debugging should now work with more recent versions of GDB
• GDB remote debugging should now work on more recent versions of Windows
• Overlapping instructions in self-modifying code no longer causes incorrect behavior
• Z80 instructions "in c" and "out c" now work correclty on 32-bit builds
• Specifying an output audio frequency higher than the FM frequency no longer deadlocks the emulator
• Fixed memory map generation for games with 3MB ROM and SRAM at the 3MB mark

Accuracy/Completeness Improvements

• YM2612 SSG-EG and CSM modes are now implemented
• VDP Mode 4 is now implemented in both Genesis and SMS mode
• Basic emulation of refresh delays has been added
• 68K interrupt latency has been made more accurate
• CRAM contention artifacts (aka CRAM dots) are now emulated
• DIVU/DIVS and MULU/MULS are now cycle accurate
• MOVEM now performs the extra ignored read and has correct timing
• The timing of serveral other 68K instructions has been fixed
• Implemented 68K trace mode
• SBCD flag calculation now matches hardware in 100% of cases
• 68K -> VDP DMA now properly has a delay at DMA start rather than at the end of the transfer
• A number of illegal effective address mode/operation combinations now properly decode as illegal instructions
• Added emulation of the slow rise time of an IO pin that was changed to an input when it was previously outputting 0
• Partial support for the VDP test register
• Partial support for the 128KB VRAM mode bit
• Improved accuracy of low level sprite rendering details
• Fixed handling of active/passive display transitions so that border extension tricks work
• Fixed handling of horizontal interrupts in extended display areas
• More accurate correspondance between horizontal counter and raster beam
• Partial emulation of serial IO registers

Other Changes

• Added Japanese version of Street Fighter 2: The New Challengers to ROM DB
• Added the following EEPROM games to the ROM DB:
  • Ninja Burai Densetsu
  • Rockman Mega World
• Added ROM DB entries for the following games with incorrect region headers:
  • Another World (E)
  • Alien Soldier (J)
  • Light Crusader (J)
  • Castle of Illusion - Fushigi no Oshiro Daibouken (J)
  • Atomic Robo-Kid (J)
• Added ROM DB entries for the following games which are incompatible with 6-button controllers:
  • King of Monsters
  • Combat Cars
  • Second Samurai
  • Dungeons & Dragons - Warriors of the Eternal Sun
• Added ROM DB entries for the following games with fixed value registers:
  • Ya Se Chuan Sho
  • 16 Zhang Ma Jiang
  • Elf Wor
  • Huan Le Tao Qi Shu: Smart Mouse
  • Mighty Morphin' Power Ranges: The Fighting Edition
  • Super Bubble Bobble MD
  • Thunderbolt II
• Added ROM DBentries for teh following games that have bad/missing SRAM headers:
  • Hardball III
  • Might and Magic - Gates to Another World
  • Might and Magic III - Isles of Terra

0.4.1

Released August 6th, 2016

New Features

• Basic support for the Saturn Keyboard adapter peripheral
• You can now navigate up to a drive selection on Windows
• Added support for binding more "special" keys

Bugfixes

• It's now possible to navigate to the root directory on Unix-like systems
• Fixed a bug in movep.l
• Fixed a crash bug in the memory management code
• Fixed a bug in the header parsing code, that caused a crash when the "International Name" field was empty
• Fixed some minor graphical corruption in Sonic 2 split-screen caused by a bug in vflip combined with interlace mode
• Corrected the PC value pushed onto the stack for line A emulator and line F emulator traps
• Fixed a bug in ensure_dir_exists that would cause it to fail to create directories in some cases when mixed path separators were used
• Fixed a bug that would result in a buffer overflow when starting a game with a long title from the menu

Accuracy

• All Z80 instructions now implemented
• Z80 half-carry flag is now fully implemented
• Implemented undocumented Z80 flag bits
• R register is now incremented appropriately
• Redundant opcode prefixes are now handled properly
• Z80 core now passes ZEXALL!

Other Changes

• Added Buck Rogers to the ROM DB
• Added Wonder Boy in Monster World to the ROM DB (for real this time)
• Added Evander 'Real Deal' Holyfield's Boxing to the ROM DB
• Slightly better handling of directory read errors
• Added "Special Thanks" to About menu
• Use local app data folder for saves and config files on Windows rather than Unix-style locations

0.4.0

New Features

• Genesis ROM based Graphical User Interface - command line is no longer required for basic functionality
• Added support for the Mega/Sega Mouse
• Configurable low pass filter
• 68000 overclock and underclock
• Scanlines can now be controlled via the config file and defaults to off (previously was always on)
• VSync can now be specified via the config file and defaults to off (previously just used the OS/driver default)
• Fullscreen mode can now be specified via the config file in addition to the command line flag
• New 68K debugger command 'co' allows a list of commands to be run each time a breakpoint is hit
• 68K debugger now supports the 'di' command like the Z80 debugger
• New debugger command 'yt' displays YM-2612 timer info
• Added support for controller hotplug (game controllers don't need to be plugged in before starting BlastEm)
• IO devices can now be automatically configured by ROM DB entries

Bugfixes

• Fixed calculation of window start column - removes graphical glitches in Afterburner 2, Fireshark, Dungeons and Dragons: Warriors of the Eternal Sun and probably others
• Fixed the implementation of LDD and LDDR
• Fixed ABCD/SBCD - eliminates the score counter problem in Bubsy
• Fixed btst when used with immediate destination - Fixes a crash in NHL 95
• Fixed YM-2612 attack phase and sustain level
• Fixed mapping of YM-2612 key on/off bits to operators
• Fixed YM-2612 LFO AMS shift values
• Fixed YM-2612 LFO phase modulation
• Fixed mapping of registers to operators in Channel 3 special mode (for real this time)
• Fixed a small bug in YM-2612 timer reloads
• Fixed peripheral ID for 3-button pad
• Accesses by the 68K to the low 4MB of the address space, but outside of the defined ROM will no longer cause a crash
• Config files and shaders saved with Windows-style line endings will no longer fail to load
• Fixed a crash bug on Windows by properly detecting invalid destination modes for immediate variant opcodes

Accuracy/Completeness Improvements

• All 68000 instructions are now implemented
• Implemented 68000 privilege, address error and illegal instruction exceptions
• Z80 half carry flag is now implemented for the trivial cases
• Fixed timing of the Z80 IM and certain LD variants
• Implemented interrupt latency - Fixes Sesame Street: Counting Cafe
• Interrupts are know acknowleged based on what the VDP thinks its asserting rather than what the 68K actually is acking - Fixes Fatal Rewind
• Improved timing of 68000 interrupt processing
• Improved timing of Z80 busack response - Fixes a crash in Barkley: Shut Up and Jam
• Adjusted the amount of time the 68000 is blocked during DMA - gets rid of remaining part of "YOUR EMULATOR SUX" text in overdrive
• Corrected order individual words of a longword are written when the predecrement addressing mode is used as the destination of a move instruction
• Adjusted relationship between Horizontal counter and render events to better match tests/measurements
• Adjusted vertical interrupt timing to better match measurements
• Improved timing of 68K/Z80 interactions based on tests

Other Changes

• Z80 disassembler now supports a start offset parameter: -s
• Windows build now uses link time optimization like the others
• Optimized the VDP code
• Improved audio resampling
• Added Mega Man - The Wily Wars to ROM database
• Added Wonder Boy in Monster World to ROM database

0.3.1

New Features

• BlastEm will now open a new terminal window when starting the debugger if it's not attached to one
• Errors are displayed in a message box if no terminal is attached
• Pure SDL render path for when OpenGL 2 is unavailable (thanks Higor Eurípedes)

Bugfixes

• GDB remote debugging works again
• Fixed a name conflict that prevented vgmplay from being built on OS X

Other Changes

• Windows build now includes the disassemblers, VGM player and save state viewer

0.3.0

New Features

• 32-bit x86 CPUs are now supported
• BlastEm is now available for OS X and Windows
• Finished support for the Sega mapper used by Super Street Fighter 2
• Added support for EEPROM saves
• Added support for large flat-mapped ROMs (used by some homebrew ROMS)
• New 68K debugger command bt (backtrace)
• I/O devices (gamepads and other peripherals) can now be configured in blastem.cfg
• VDP Debugger views from before 0.1.0 have been restored

Bugfixes

• Partial emulation of floating bus bits for certain I/O regs (fixes Super Offroad 2)
• Fixed shadow/highlight mode
• Implemented AM and fixed LFO update speed
• Fixed negative detune values
• Corrected register to operator mapping for channel 3 special mode
• Initial stab at emulating cycles being stolen from the 68K when the Z80 accesses its bus
• Better handling of creating a savestate in "uncooperative" games/demos
• Implemented VSCROLL latching
• Fixed a bug that would corrupt the Z80's SP register in some situations
• Fixed PAL flag in VDP status register
• Fixed HV counter
• Fixed flag calculation for RRA, RRCA, RLA and RLCA
• Fixed instruction timing for RR, RRC, RL and RLC when using the IX or IY registers
• Fixed access to the I and R registers

Other Changes

• Upgraded to SDL2
• Dropped suport for the non-OpenGL render path
• Linux builds should now work on something other than the specific version of Ubuntu I happen to be using at build time
• BlastEm now syncs at least once per line by default. You can change this behavior with the max_clocks config value

0.2.0

New Features

• Added Turbo and Slow modes that overclock and underclock the system respectively
• Added FPS counter
• New OpenGL render backend that allows filters to be writte in GLSL
• Support 'UI' bindings on gamepad buttons and dpads
• GDB remote debugging support
• New debugger 68K debugger commands o, s and zp (see README for details)

Bugfixes

• Fixed argument handling so that the ROM filename does not need to be specified first
• Don't allow register writes to Mode 5 only regs when in Mode 4
• Fixed a bunch of VDP edge case behavior checked by Nemesis's test ROM
• Fixed operator 1 self-feedback
• Fixed handling of envelope overflow in attack phase
• Fixed handling of channel output overflow
• Adjusted FM and PSG volume to better match real hardware
• Improved YM-2612 busy flag emulation
• Properly sync hardware at end of frame when the 68K is blocked by DMA
• Approximate wait state behavior when the Z80 accesses the 68K's bus
• Implemented HV counter latch
• Implemented sprite overflow and collision flags
• Fixed the timing of several Z80 instructions

0.1.0

Initial Release