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buffering, PCM DMA, memcpy12bswap
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@ -3,43 +3,149 @@ About
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-----
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This version of PicoDrive is another enhanced version of Dave's
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Megadrive / Genesis emulator for Pocket PC. The original Dave's code was
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heavily modified (including Cyclone core), parts of it were rewritten in
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asm, many features added, accuracy increased. This version is aimed at
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ARM-based handheld devices, so ports exist for GP2X handheld console,
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Symbian smartphones and PocketPC devices.
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Megadrive / Genesis emulator for Pocket PC, which now can also emulate
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Sega/Mega CD. The original Dave's code was heavily modified (including
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Cyclone core), parts of it were rewritten in asm, many features added,
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accuracy increased. Sega/Mega CD emulation is mostly based on Gens code.
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This version is aimed at ARM-based handheld devices, so ports exist for
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GP2X handheld console, Symbian smartphones and other devices.
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How to make it run
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------------------
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GP2X:
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Copy PicoDrive.gpe, code940.bin and mmuhack.o to any place in your filesystem
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(all 3 files must be in the same directory) and run PicoDrive.gpe.
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Then load a ROM and enjoy!
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Then load a ROM and enjoy! ROMs can be in .smd or .bin format and can be zipped.
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Symbian:
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Select PicoDrive from application (tools) menu and run it. That's it!
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All:
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If you have any problems (game does not boot, sound is glitchy, broken graphics),
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make sure you enable "Accurate timing", "Emulate Z80" and then disable
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"Fast renderer". This way you will get the best compatibility this emulator can
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provide.
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How to run Sega/Mega CD games
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-----------------------------
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To play any game, you need BIOS files. These files must be copied to the same
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directory as PicoDrive.gpe. Files can be named as follows:
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US: us_scd1_9210.bin us_scd2_9306.bin SegaCDBIOS9303.bin
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EU: eu_mcd1_9210.bin eu_mcd2_9303.bin eu_mcd2_9306.bin
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JP: jp_mcd1_9112.bin jp_mcd1_9111.bin
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these files can also be zipped.
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The game must be dumped to ISO format, but BIN can be used too. If you want
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CD music, you must use ISO+mp3 files. Audio from BIN files won't be read at
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all due to SD access issues. Also BIN files are usually larger, so it's better
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to use ISO. ISO+mp3 files can be named similarly as for other emus.
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Here are some examples:
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SonicCD.iso data track
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SonicCD_02.mp3 audio track 1 (CD track 2)
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SonicCD_03.mp3
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...
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Sonic the Hedgehog CD (US) - Track 01.iso
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Sonic the Hedgehog CD (US) - Track 02.mp3
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Sonic the Hedgehog CD (US) - Track 03.mp3
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...
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ISO files can also be zipped (but not mp3 files, as they are already
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compressed). Note that this can cause very long loading times, which may
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take up to several minutes. File naming is similar as with uncompressed ISOs.
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Example:
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SonicCD.zip data track
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SonicCD_02.mp3 audio track 1 (CD track 2)
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SonicCD_03.mp3
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...
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Configuration
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-------------
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See config.txt file.
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Other important stuff
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---------------------
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* When you use both GP2X CPUs, keep in mind that you can't overclock as high as
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when using ARM920 only. For example my GP2X when run singlecore can reach
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280MHz, but with both cores it's about 250MHz. When overclocked too much,
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it may start hanging and producing random noise.
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* PicoDrive is not a mp3 player, so all mp3s MUST be encoded at 44.1kHz stereo.
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Otherwise mp3s will play too fast or too slow.
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* Due to internal implementation mp3s must not be larger that ~15MB
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(15548416 bytes). Larger mp3s will not be fully loaded.
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* Use lower bitrate for better performance (96 or 128kbps CBRs recommended).
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* RAM timings option is good for dualcore operation (it is disabled by
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default because it doesn't work on every GP2X, so enable it in advanced
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options).
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Cheat support
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-------------
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To use GG/patch codes, you must type them into your favorite text editor, one
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per line. Comments may follow code after a whitespace. Only GameGenie and
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Genecyst patch formats are supported.
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Examples:
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Genecyst patch (this example is for Sonic):
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00334A:0005 Start with five lives
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012D24:0001 Keep invincibility until end of stage
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009C76:5478 each ring worth 2
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009C76:5678 each ring worth 3
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...
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Game Genie patch (for Sonic 2):
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ACLA-ATD4 Hidden palace instead of death egg in level select
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...
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Both GG and patch codes can be mixed in one file.
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When the file is ready, name it just like your ROM file, but with additional
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.pat extension, making sure that case matches.
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Examples:
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ROM: Sonic.zip
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PATCH FILE: Sonic.zip.pat
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ROM: Sonic 2.bin
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PATCH FILE: Sonic 2.bin.pat
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Put the file into your ROMs directory. Then load the .pat file as you would
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a ROM. Then Cheat Menu Option should appear in main menu.
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What is emulated?
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-----------------
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Genesis/MegaDrive:
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main 68k @ 7.6MHz: yes, Cyclone core
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z80 @ 3.6MHz: yes, DrZ80 core
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VDP: yes, except some quirks not used by games
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YM2612 FM: yes, optimized MAME core
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SN76489 PSG: yes, MAME core
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Sega/Mega CD:
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another 68k @ 12.5MHz: yes, Cyclone too
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gfx scaling/rotation chip (custom ASIC): not yet (faked only)
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PCM sound source: yes
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CD-ROM controller: yes (mostly)
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bram (internal backup RAM): yes
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Problems / limitations
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----------------------
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* 32x, Sega CD, SVP are not emulated.
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* 32x and SVP are not emulated.
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* Various VDP quirks (window bug, scroll size 2, etc.) are not emulated,
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as very few games use this.
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as very few games use this (if any at all).
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* Some games don't work or have glitches because of inaccurate timing and sync
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between the emulated chips.
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@ -67,13 +173,18 @@ MultiArcadeMachineEmulator (MAME) development
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Texas Instruments SN76489 / SN76496 programmable tone /noise generator
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Homepage: http://www.mame.net/
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Stephane Dallongeville
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Gens, MD/Mega CD/32X emulator. Most Sega CD code is based on this emu.
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Helix community
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Helix mp3 decoder
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Additional thanks
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-----------------
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* Charles MacDonald (http://cgfm2.emuviews.com/) for old but still very useful
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info about genesis hardware.
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* Stéphane Dallongeville for creating Gens and making it open-source.
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* Steve Snake for all that he has done for Genesis emulation scene.
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* Bart Trzynadlowski for his SSFII and 68000 docs.
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* Haze for his research (http://haze.mameworld.info).
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@ -100,6 +211,47 @@ Symbian:
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Changelog
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---------
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1.2x
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+ ISO files now can be zipped. Note that this causes VERY long loading times.
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+ Added data pre-buffering support, this allows to reduce frequency of short pauses
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in FMV games, but makes those pauses longer.
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* Fixed PCM DMA transfers (intro FMV in Popful Mail).
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1.201
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+ Added basic cheat support (GameGenie and Genecyst patches).
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1.20
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* Fixed a long-standing problem in audio mixing code which caused slight distortions
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at lower sample rates.
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* Changed the way 920 and 940 communicates (again), should be more reliable and give
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slight performance increase.
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* Some optimizations in audio mixing code.
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* Some menu changes (background added, smaller font in ROM browser, savestate loader
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now can select slots).
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+ 1M mode DMA transfers implemented (used by FMV games like Night Trap and Sewer Shark).
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+ Games now can run code from WORD RAM in 1M mode (fixes Adventures of Willy Beamish).
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+ "Cell arrange" address mapping is now emulated (Heart of the alien).
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+ "Color numeric operation" is now emulated (text in Lunar 2, Silpheed intro graphics).
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+ "Better sync" option added (prevents some games from hanging).
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1.14
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+ Region autodetection now can be customized.
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* When CDDA music tracks changed, old buffer contents were incorrectly played. Fixed.
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* BRAM is now automatically formatted (no need to enter BIOS menu and format any more).
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* Games now can be reset, CDDA music no longer breaks after loading another ISO.
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* Fixed a race condition between 920 and 940 which sometimes caused CDDA music not to play.
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+ Savestates implemented for Sega/Mega CD.
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+ PCM sound added.
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* Some mixer code rewritten in asm. 22kHz and 11kHz sound rates are now supported in
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Mega CD mode (but mp3s must still be 44kHz stereo).
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+ Timer emulation added.
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* CDC DMA tansfers fixed. Snatcher and probably some more games now boot.
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* 2M word RAM -> VDP transfers fixed, no more corruption in Ecco and some other games.
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1.10
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+ GP2X: Added experimental Sega CD support.
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+ GP2X: Added partial gmv movie playback support.
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0.964
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* GP2X: Fixed a sound buffer underflow issue on lower sample rate modes, which was
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happening for NTSC games and causing sound clicks.
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@ -299,3 +451,7 @@ INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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SEGA/Genesis/MegaDrive/SEGA-CD/Mega-CD/32X are trademarks of
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Sega Enterprises Ltd.
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