Genesis-Plus-GX/source/unused/CHANGELOG

Genesis Plus History
--------------------

Note: All recent changes directly come from the Gamecube/Wii port, coded by Eke-Eke.

 [Current] (Eke-Eke)
- YM2612(MAME): fixed LFO phase update for CH3 special mode: fix sound effects in Warlock & Aladdin (thanks to AamirM)
- YM2612(MAME): fixed EG attenuation level on "KEY ON": fix Ecco 2's splash sound
- YM2612(MAME): fixed SSG-EG emulation: fix Bubba'n Stix (Track 5) and many others
- YM2612(MAME): replaced sample interpolation with libsamplerate support, High Quality mode is now more accurate
- implemented cycle-accurate HINT timings: every timing sensitive games/demos are now *finally* working fine
- fixed a bug affecting CRAM/VSRAM DMA timings
- fixed Sprite Attribute Table address mask for VRAM writes 
- improved accuracy of 68k access to Z80: fix music in Pacman 2 when entering PAUSE menu
- disabled "Address Error" emulation when UMK3 hack is loaded: fix game crashing after a round ends up
- added support for some more unlicensed games: Pocket Monster, King of Fighter 98, Soul Blade (credits to Haze)
- improved Menacer emulation: fix lightgun support in Body Count & T2: The Arcade Game
- added Konami Justifier emulation: fix lightgun support in Lethal Enforcers 1 & 2
- added Sega Mouse emulation (Populous 2, Body Count, Shangai 2, Fun'n Games, ...)

 [07/16/08] (Eke-Eke)
- adjusted (again) HINT timings: fix Double Dragon 2 (game freezed), hopefully does not break anything else
- fixed broken EEPROM support for Codemaster games
- modified input update timings: fix Dungeons & Dragons - Warriors of the Eternal Sun (thanks to Notaz)
- added support for "Ultimate Mortal Kombat Trilogy" hack (max. size supported is 10MBytes)
- added (VERY) preliminar support for PICO roms (credits to Notaz for his documentation)
- improved YM2612 emulation (credits to Nemesis for his tests on real hardware):
  .implemented phase overflow emulation: improved fix for special music instrument used in Comix Zone, Flashback, Ariel, Shaq Fu...
  .improved SSG-EG emulation in MAME core (also based on additional code from Alone Coder)
  .improved Timers emulation accuracy
  .improved Enveloppe Generator accuracy
  .fixed Channel 3 CSM mode emulation
  .implemented sample interpolation in MAME core to emulate the chip at original frequency (HQ YM2612 mode, from gens)

 [06/01/08] (Eke-Eke)
- improved HCounter accuracy: fix graphic glitches in "Striker (Europe)"
- improved HINT timing accuracy: fix flickering in "Zero The Kamikaze Squirrel (USA)"
- improved rendering accuracy when backdrop color is modified during HBLANK (Road Rash I/II/III)
- fixed broken Game Genie support
 
 [04/19/08] (Eke-Eke)
- modified VINT timings a little bit: fix lockup during Desert Strike's intro
- corrected 68k interrupts handling: fix graphic glitches in Darius II/Sagaia
  
 [04/06/08] (Eke-Eke)
- updated SVP core: fix some perspective issues in Virtua Racing (thanks to Notaz)
- added internal SAT update during VRAM Fill: fix unmasked sprites during Battletech's intro
- fixed m68k core issues with gcc 4.2.3: fix Xperts, Lemmings 2, M1 Abrams Battle Tank
- forced YM2612 Enveloppe update: fix intro music in Batman&Robin (thanks to Aamir)

 [03/01/08] (Eke-Eke)
- added SVP emulation: Virtua Racing is now emulated (big thanks to Notaz and TascoDeluxe)
- fixed VDP registers behaviour when VDP Mode 4 is enabled: fix Bass Masters Classic Pro, Captain Planet & The Planeeters
- corrected a bug in DMA Fill operation: fix James Pond 3, Rockman World/Megaman Willy Wars (corrupted VRAM)
- corrected typo errors in CPU cycle counters update: fix optiom screen music in "College Slam" and probably others games.
- added preliminary support of undocumented YM2612 bug: fixes soundtracks of Shaq Fu, Spiderman, Comix Zone, Ariel and some others
- added support for mappers & copy protection devices used in many unlicensed/pirate cartridges (see cart_hw.c for details)
- rewrote memory handlers for better modularity and some (little) speedup
- reduced Savestate size

 [01/07/08] (Eke-Eke)
- fixed interleaved rom detection: roms with .smd extension should now work fine
- fixed a recently introduced bug in VDP registers writes: fixes bad colors in Toy Story (intro)
- updated list of games using EEPROM: added Sports Talk Baseball (internal memory check fixed) and Brian Lara Cricket
- fixed VINT flag update when VINT is disabled: fixes NCAA College Football
- adjusted DMA timings in H32 mode: fixes flickering in Out of this World, Kawasaki Superbike Challenge & Formula One
- adjusted line rendering and HBLANK timings: fixes flickering in Nigel Mansell's World Championship Racing, Deadly Moves/Power Athlete
- fixed unmapped ROM reads through Z80 Bank: fixes Zombie High (Proto)
- added support for custom ROM/RAM mapping used by Game no Kanzume Otokuyou

 [12/28/07] (Eke-Eke)
- many sourcecode cleanup and optimization
- completely rewrote EEPROM emulation: now support all known EEPROM types (24C01-24C65) and mappers (Sega, Acclaim, EA, Codemasters)
used in a few games (now use internal game database) as external RAM. This should at least fix save support in the following games:
  . NBA Jam (alternate Acclaim mapper)
  . College Slam, Frank Thomas Big Hurt Baseball (24C65 type)
  . NHLPA Hockey 93, Rings of Power (EA mapper)
  . Micro Machines serie, Brian Lara Cricket 96/Shane Warne Cricket (Codemasters mapper)
- external RAM is now initialized to 0xFF by default: fix Micromachines 2, Dino Dini Soccer 
- fixed SRAM 16-bits memory handlers: fix some Sega Sports and EA Sports games (NFL95, NBA Action 95, NHL97, NHL98,...)
- modified WRITE_xxx & READ_xxx macros for better portability and faster memory access on BIG ENDIAN platform 
- completely rewrote BIG ENDIAN support in render.c and vdp.c: rendering should be a little faster
- rewrote ROM bankswitch emulation (Super Street Fighter II): ROM access are faster, using memory pointers instead of reading ROM copy from ARAM 
- fixed leftmost Window/PlaneA column render and implemented Window bug (as described by Charles Mc Donald)
- improved "Sprite Limit" and "Sprite Collision" detection accuracy
- modified RGB565 Color Palette to use the full available color range (0-31;0-63)
- implemented "cycle accurate" HV Interrupt timings: fix Sesame's Street Counting Cafe, Legend of Galahad (intro)
- improved VDP access timings accuracy (added FIFO emulation): fix Double Clutch
- improved DMA timings accuracy: fix Winter Olympics (E), Arch Rivals and probably more
- fixed HCounter again: Road Rash serie (I,II,III) don't need timing hacks anymore
- fixed VCounter in Interlaced 2 mode: fix Combat Cars "VS-Mode"
- improved Interlaced 2 mode (double resolution) rendering: Sonic 2, Combat Cars ("VS-Modes") look far better
- added TMSS BIOS support (optional)
- rewrote part of the YM2162 MAME's core: fixed internal FM timers handling, removed non-YM2612 emulation code and unused multiple cpu support
- implemented "cycle accurate" FM timers & sound samples rendering
- improved Z80 Interrupt timing accuracy: fix Sonic 3 music slowdowns
- updated Z80 & 68000 cores to last MAME versions
- improved Soft Reset emulation: X-Men 2 and Eternal Champions (random character selection) now work more like on real hardware.
- added full overscan emulation (vertical & horizontal borders) for "pixel perfect" aspect ratio (tested against a real genesis)

 [07/20/07] (Eke-Eke)
- corrected TeamPlayer support: fix multiplayer in Gauntlet 4 (Sept. version), Pengo and a lot of others
- added J-Cart support: enable multiplayer in Codemasters games (Pete Sampras, Micromachines games, Super Skidmarks)
- added serial EEPROM autodetection: fix games with bad SRAM informations in header (NBA Jam TE)
- added SVP faking: display 2D graphics in Virtua Racing (the game is however still unplayable)
- added support for more internal IO registers: fixe some unlicensed games (Wisdom Tree games...)
- added preliminary support for unmapped protection device: fix some unlicensed games with special built-in hardware (Squirell King, Lion King 2...)
- added "Soft Reset" combo (in game, use L+Z triggers): this should be like pressing the RESET button on a real Genesis and this is required
  in some games to enable special features or even complete the game (ex: X-Men).

 [06/21/07] (Eke-Eke)
- added Multitap support (EA 4-Way Play and Sega Teamplayer): allowed up to four players in games supporting those peripherals
- added partial Sega Menacer lightgun support (use Analog Stick): automatically set when detecting the 6-in-1 Menacer game

 [05/18/07] (Eke-Eke)
- you can now switch between FM cores without reseting the game. FM registers  value are automatically restored when switching.
- removed the previous VINT timings modification because it brokes some games (Rocket Knight, Thunderforce III,...)
- added automatic Timing configuration (VDP latency, VINT timing & alternate Line Timing) at game loading, based upon specific romname detection.
This means you can still modify some of these options afterwards but they are now automatically set/unset when loading a game which need
special timing fixes. These fixes are also automatically desactivated when the current game doesn't need them.
For information, games that are actually detected and need special timings to run properly are:
 .Legend of Galahad & Road Rash series (single line not rendered properly)
 .Sesame Street Counting Cafe (don't boot)
 .Chaos Engine/Soldiers of Fortune (graphic glitches on scrolling)

 [05/08/07] (Eke-Eke)
- VINT timings are now a little more accurate: fixes Sesame's Street Counting Cafe
- SN76496 MAX_OUTPUT back to normal
- modified FB_WNOISE value in SN76496 core according to John Kortink's last informations 
- added support for Maxim's PSG core, same as used in SMSPLUS (it becomes the default PSG core)
- updated FM core to the latest MAME version
- corrected DAC output level (fixes voices and some special FX being too low)
- added support for Gens YM2612 (FM) core (MAME's one still remains default FM core)
- added configurable preamplification for each sound cores (see Emulator Options)
- added some other configurable sound options (boost overall volume, FM improvment for Gens YM2612)

 [04/11/07] (Eke-Eke)
- corrected MAX_OUTPUT value in SN76496 core: fix PSG sound (SFX) volume

 [03/17/07] (Eke-Eke)
 - added an option to enable alternate line rendering timing (fix single line error in Road Rash series and Legend of Galahad's Intro)
 - Color RAM update now always reset color 0 to border color (fix color glitches in Mortal Kombat,...) (thanks to Noop's for the idea)

 [03/09/07] (Eke-Eke)
- modified HV counter tables (fix graphic glitches in Skitchin's sky, Lotus 2 Recs, Panorama Cotton, Dashin Desperados & maybe more)
- completely rewrote DMA timings emulation so that it works for all games (no more cpu freezing)
- added all DMA tranfer rates handling for each three DMA modes and added dma busy flag emulation
- modified interrupts handling on VDP register #0 and #1 writes (fix Lemmings status bar)
- added VDP RAM write latency  (fix Chaos Engine/Soldier of Fortune gfx glitches)
- modified FM timers handling a bit (fix Vectorman2 music)
- corrected Sprite Limit rendering (fix Sonic 1 & Micromachines 2 title screens)
- corrected IO Registers writes (fix Decap' Attack controls, no more need for alternate input)
- corrected 6 Buttons Pad emulation (fix 6buttons detection in Mortal Kombat 3, Comix Zone and other 6-buttons compatible games)
- modified sound mixing a bit according to Generator sourcecode (FM and PSG ratios seems more correct)

 [02/07/07] (Eke-Eke)
- fixed fm timers (fix missing music in Castle of Illusion, Quackshot, Undead Line, Wonderboy in Monster Lair, Cal 50, Turbo Outrun, Thundeforce 4 and maybe more)
- added complete EEPROM emulation (save support now works fine in Wonderboy5, Megaman Willy Wars, NBA Jam...)  (credits to Notaz, adapted from Picodrive code)
- added preliminar dma timing emulation (fix bottom screen in Legend of Galahad) (credits to Notaz, adapted from Picodrive code)
- hack: clear Vint pending after Hint (INT level 4) acknowledge (fix Fatal Rewind)
- hack: modify read_bus16 to return a random value (fake fetch) (fix Time Killers)
- modified cpu execution timings, with more correct hblank and interrupts timing  (fix ISS Deluxe, Double Dragon 2 and certainly more) (Based on Gens code)
- modified busreq mechanism: better synchro between z80 & 68k (no need to dejitter anymore) (Based on Gens code)
- added sprite collision detection (fix Strider 2)
- modified dma fill operation for big endian platform (fix Contra Hardcorps gfx garbage)

 [05/25/03]
 - Fixed a typo that made Z80 banked access to the VDP registers always fail.

 [05/17/03]
 - Modified the rendering code to handle unaligned longword access to memory.

 [04/20/03]
 - Modified 68000 emulator to prevent 'tas.b $mem' from writing data back
   after a read (fixes Gargoyles).
 - Fixed bug in 68000 emulator to swap order of words written for address
   register indirect pre-decremented writes (fixes Jim Power graphics).
 - Added support for 240-line displays (for Super Skidmarks).
 - Rewrote part of the interrupt handling (fixes some raster effects).
 - Removed sprite collision detection code (never really worked).
 - Optimized sprite rendering inner loop.

 [04/13/03]
 - Finished up memory map for VDP DMA V-bus reads.
 - Fixed handling of 68000 writes to I/O chip at even addresses.
 - Fixed bit 7 handling of control register in I/O chip.
 - Finished up Z80 memory map.
 - Added code to handle Genesis hardware lock-ups.
 - Removed some faulty code from the 68000 memory map handlers.

 [03/22/03]
 - Completed implementation of Z80 banked memory handlers.