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[Core/CD] improved CDD "play" command accuracy (fixes "Snatcher" Act 2 starting cutscene)

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This commit is contained in:
EkeEke 2016-07-03 15:52:17 +02:00
parent 101afae137
commit 38753afaa5
5 changed files with 11 additions and 9 deletions
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2
HISTORY.txt
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@ -20,6 +20,8 @@ Genesis Plus GX 1.7.5 (xx/xx/xxxx) (Eke-Eke)
* improved savestate format
* improved Sub-CPU synchronization with Main-CPU (fixes "Soul Star")
* improved Main-CPU & Sub-CPU idle loop detection (fixes "Super League CD")
* improved PAL Mega CD timing accuracy (fixes PAL "Snatcher" intro synchronization)
* improved CDD "play" command accuracy (fixes "Snatcher" Act 2 starting cutscene)
* disabled 68k and Z80 access to PRG-RAM when SUB-CPU is running (fixes "Dungeon Explorer")
* disabled CD hardware reset on Soft-Reset (verified on real hardware)
* fixed DATA track minimal length (fixes BIOS refusing to boot small homebrew demos)

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builds/genesis_plus_gx_libretro.dll
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builds/genplus_cube.dol
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18
core/cd_hw/cdd.c
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@ -1444,8 +1444,8 @@ void cdd_process(void)
/* unless RS1 indicated invalid track infos */
if (scd.regs[0x38>>1].byte.l == 0x0f)
{
/* and SEEK has ended */
if (cdd.status != CD_SEEK)
/* and drive is now ready */
if (!cdd.latency)
{
/* then return valid track infos, e.g current track number in RS2-RS3 (fixes Lunar - The Silver Star) */
scd.regs[0x38>>1].byte.l = 0x02;
@ -1568,7 +1568,7 @@ void cdd_process(void)
/* CD drive latency */
if (!cdd.latency)
{
/* Fixes a few games hanging during intro because they expect data to be read with some delay */
/* Fixes a few games hanging because they expect data to be read with some delay */
/* Radical Rex needs at least one interrupt delay */
/* Wolf Team games (Anet Futatabi, Cobra Command, Earnest Evans, Road Avenger & Time Gal) need at least 10 interrupts delay */
/* Space Adventure Cobra (2nd morgue scene) needs at least 13 interrupts delay (incl. seek time, so 10 is OK) */
@ -1655,13 +1655,13 @@ void cdd_process(void)
/* update status */
cdd.status = CD_PLAY;
/* return track index in RS2-RS3 */
scd.regs[0x38>>1].w = (CD_PLAY << 8) | 0x02;
scd.regs[0x3a>>1].w = (cdd.index < cdd.toc.last) ? lut_BCD_16[index + 1] : 0x0A0A;
/* RS1=0xf to invalidate track infos in RS2-RS8 until drive is ready (fixes Snatcher Act 2 start cutscene) */
scd.regs[0x38>>1].w = (CD_PLAY << 8) | 0x0f;
scd.regs[0x3a>>1].w = 0x0000;
scd.regs[0x3c>>1].w = 0x0000;
scd.regs[0x3e>>1].w = 0x0000;
scd.regs[0x40>>1].byte.h = 0x00;
break;
scd.regs[0x40>>1].w = ~(CD_PLAY + 0xf) & 0x0f;
return;
}
case 0x04: /* Seek */
@ -1753,7 +1753,7 @@ void cdd_process(void)
/* update status */
cdd.status = CD_SEEK;
/* unknown RS1-RS8 values (returning 0xF in RS1 invalidates track infos in RS2-RS8 and fixes Final Fight CD intro when seek time is emulated) */
/* RS1=0xf to invalidate track infos in RS2-RS8 while seeking (fixes Final Fight CD intro when seek time is emulated) */
scd.regs[0x38>>1].w = (CD_SEEK << 8) | 0x0f;
scd.regs[0x3a>>1].w = 0x0000;
scd.regs[0x3c>>1].w = 0x0000;