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Genesis-Plus-GX/source/cd_hw/cdd.c
EkeEke ae1416aad4 .improved CDD TOC emulation robustness 
.added support for "Fast Forward" and "Fast Rewind" CDD commands
.modified default length of simulated CD audio tracks
2012-07-15 17:15:01 +02:00

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/***************************************************************************************
* Genesis Plus
* CD drive processor
*
* Copyright (C) 2012 Eke-Eke (Genesis Plus GX)
*
* Redistribution and use of this code or any derivative works are permitted
* provided that the following conditions are met:
*
* - Redistributions may not be sold, nor may they be used in a commercial
* product or activity.
*
* - Redistributions that are modified from the original source must include the
* complete source code, including the source code for all components used by a
* binary built from the modified sources. However, as a special exception, the
* source code distributed need not include anything that is normally distributed
* (in either source or binary form) with the major components (compiler, kernel,
* and so on) of the operating system on which the executable runs, unless that
* component itself accompanies the executable.
*
* - Redistributions must reproduce the above copyright notice, this list of
* conditions and the following disclaimer in the documentation and/or other
* materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************************/
#include "shared.h"
#define NO_DISC 0x00
#define CD_PLAY 0x01
#define CD_SEEK 0x02
#define CD_SCAN 0x03
#define CD_READY 0x04
#define CD_OPEN 0x05
#define CD_STOP 0x09
/* BCD conversion lookup tables */
static const uint8 lut_BCD_8[100] =
{
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09,
0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19,
0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29,
0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,
0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,
0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,
0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99,
};
static const uint16 lut_BCD_16[100] =
{
0x0000, 0x0001, 0x0002, 0x0003, 0x0004, 0x0005, 0x0006, 0x0007, 0x0008, 0x0009,
0x0100, 0x0101, 0x0102, 0x0103, 0x0104, 0x0105, 0x0106, 0x0107, 0x0108, 0x0109,
0x0200, 0x0201, 0x0202, 0x0203, 0x0204, 0x0205, 0x0206, 0x0207, 0x0208, 0x0209,
0x0300, 0x0301, 0x0302, 0x0303, 0x0304, 0x0305, 0x0306, 0x0307, 0x0308, 0x0309,
0x0400, 0x0401, 0x0402, 0x0403, 0x0404, 0x0405, 0x0406, 0x0407, 0x0408, 0x0409,
0x0500, 0x0501, 0x0502, 0x0503, 0x0504, 0x0505, 0x0506, 0x0507, 0x0508, 0x0509,
0x0600, 0x0601, 0x0602, 0x0603, 0x0604, 0x0605, 0x0606, 0x0607, 0x0608, 0x0609,
0x0700, 0x0701, 0x0702, 0x0703, 0x0704, 0x0705, 0x0706, 0x0707, 0x0708, 0x0709,
0x0800, 0x0801, 0x0802, 0x0803, 0x0804, 0x0805, 0x0806, 0x0807, 0x0808, 0x0809,
0x0900, 0x0901, 0x0902, 0x0903, 0x0904, 0x0905, 0x0906, 0x0907, 0x0908, 0x0909,
};
static const uint16 toc_snatcher[21] =
{
56014, 495, 10120, 20555, 1580, 5417, 12502, 16090, 6553, 9681,
8148, 20228, 8622, 6142, 5858, 1287, 7424, 3535, 31697, 2485,
31380
};
void cdd_init(void)
{
}
void cdd_reset(void)
{
/* reset cycle counter */
cdd.cycles = 0;
/* reset disc read latency */
cdd.latency = 0;
/* reset track index */
cdd.index = 0;
/* reset logical block address */
cdd.lba = 0;
/* reset status */
cdd.status = cdd.loaded ? CD_READY : NO_DISC;
}
void cdd_load(char *filename, int type_bin)
{
/* unload any disc first */
cdd_unload();
/* CD image file format */
if (type_bin)
{
/* BIN format (2352 bytes block data) */
cdd.sectorSize = 2352;
}
else
{
/* ISO format (2048 bytes block data) */
cdd.sectorSize = 2048;
}
/* load DATA track */
cdd.toc.tracks[0].fd = fopen(filename,"rb");
if (cdd.toc.tracks[0].fd)
{
/* DATA track start (logical block 0) */
cdd.toc.tracks[0].start = 0;
/* DATA track length */
fseek(cdd.toc.tracks[0].fd, 0, SEEK_END);
cdd.toc.tracks[0].end = ftell(cdd.toc.tracks[0].fd) / cdd.sectorSize;
fseek(cdd.toc.tracks[0].fd, 0, SEEK_SET);
/* initialize TOC */
cdd.toc.end = cdd.toc.tracks[0].end;
cdd.toc.last = 1;
/* TODO: add audio track support from BIN/CUE, ISO/WAV, MP3, OGG ? */
/* Simulated audio tracks if none found */
if (cdd.toc.last == 1)
{
/* Some games require specific TOC infos */
if (strstr(rominfo.product,"T-95035") != NULL)
{
/* Snatcher */
do
{
cdd.toc.tracks[cdd.toc.last].start = cdd.toc.end + 2*75;
cdd.toc.tracks[cdd.toc.last].end = cdd.toc.tracks[cdd.toc.last].start + toc_snatcher[cdd.toc.last];
cdd.toc.end = cdd.toc.tracks[cdd.toc.last].end;
cdd.toc.last++;
}
while (cdd.toc.last < 21);
}
else if (strstr(rominfo.product,"T-45074") != NULL)
{
/* Lunar - Eternal Blue (J) */
cdd.toc.tracks[1].start = cdd.toc.end + 2*75;
cdd.toc.tracks[1].end = cdd.toc.tracks[1].start + 21654;
cdd.toc.end = cdd.toc.tracks[1].end;
cdd.toc.tracks[2].start = cdd.toc.end + 2*75;
cdd.toc.tracks[2].end = cdd.toc.tracks[2].start + 5004;
cdd.toc.end = cdd.toc.tracks[2].end;
cdd.toc.tracks[3].start = cdd.toc.end + 2*75;
cdd.toc.tracks[3].end = cdd.toc.tracks[3].start + 684;
cdd.toc.end = cdd.toc.tracks[3].end;
cdd.toc.last = 4;
}
else if (strstr(rominfo.product,"T-127045") != NULL)
{
/* Lunar - Eternal Blue (U) */
cdd.toc.tracks[1].start = cdd.toc.end + 2*75;
cdd.toc.tracks[1].end = cdd.toc.tracks[1].start + 21735;
cdd.toc.end = cdd.toc.tracks[1].end;
cdd.toc.tracks[2].start = cdd.toc.end + 2*75;
cdd.toc.tracks[2].end = cdd.toc.tracks[2].start + 27131;
cdd.toc.end = cdd.toc.tracks[2].end;
cdd.toc.last = 3;
}
else
{
/* default TOC (99 x 2s) */
do
{
cdd.toc.tracks[cdd.toc.last].start = cdd.toc.end + 2*75;
cdd.toc.tracks[cdd.toc.last].end = cdd.toc.tracks[cdd.toc.last].start + 2*75;
cdd.toc.end = cdd.toc.tracks[cdd.toc.last].end;
cdd.toc.last++;
}
while ((cdd.toc.last < 99) && (cdd.toc.end < 56*60*75));
}
}
/* CD loaded */
cdd.loaded = 1;
}
}
void cdd_unload(void)
{
if (cdd.loaded)
{
int i;
/* close CD tracks */
for (i=0; i<cdd.toc.last; i++)
{
if (cdd.toc.tracks[i].fd)
{
fclose(cdd.toc.tracks[i].fd);
}
}
/* CD unloaded */
cdd.loaded = 0;
}
/* reset TOC */
memset(&cdd.toc, 0x00, sizeof(cdd.toc));
/* unknown CD image file format */
cdd.sectorSize = 0;
}
void cdd_read(uint8 *dst)
{
/* start reading from sector 0 */
if (cdd.lba >= 0)
{
/* BIN format ? */
if (cdd.sectorSize == 2352)
{
/* skip 16-byte header */
fseek(cdd.toc.tracks[0].fd, cdd.lba * 2352 + 16, SEEK_SET);
}
/* read sector data (MODE 1) */
fread(dst, 2048, 1, cdd.toc.tracks[0].fd);
}
}
void cdd_update(void)
{
#ifdef LOG_CDD
error("LBA = %d (track n<>%d)\n", cdd.lba, cdd.index);
#endif
/* reading track */
if (cdd.status == CD_PLAY)
{
/* read latency */
if (cdd.latency > 0)
{
cdd.latency--;
return;
}
/* track type */
if (cdd.index > 0)
{
if (cdd.index < cdd.toc.last)
{
/* audio track sector sent to CD Fader/DAC should also be sent to CDD */
cdc_decoder_update(0);
/* next sector is automatically read */
cdd.lba++;
/* check end of current track */
if (cdd.lba >= cdd.toc.tracks[cdd.index].end)
{
/* next track */
cdd.index++;
}
}
}
else
{
/* sector header (CD-ROM Mode 1) */
uint8 header[4];
uint32 msf = cdd.lba + 150;
header[0] = lut_BCD_8[(msf / 75) / 60];
header[1] = lut_BCD_8[(msf / 75) % 60];
header[2] = lut_BCD_8[(msf % 75)];
header[3] = 0x01;
/* data track sector read is controlled by CDC */
cdd.lba += cdc_decoder_update(*(uint32 *)(header));
}
}
/* fast scanning disc */
else if (cdd.status == CD_SCAN)
{
/* skip track */
cdd.lba += cdd.scanOffset;
/* check current track limits */
if (cdd.lba >= cdd.toc.tracks[cdd.index].end)
{
/* next track */
cdd.index++;
}
else if (cdd.lba < cdd.toc.tracks[cdd.index].start)
{
/* previous track */
cdd.index--;
}
/* check disc limits */
if (cdd.index < 0)
{
cdd.index = 0;
cdd.lba = 0;
}
else if (cdd.index >= cdd.toc.last)
{
cdd.index = cdd.toc.last;
cdd.lba = cdd.toc.end;
}
}
}
void cdd_process(void)
{
/* Process CDD command */
switch (scd.regs[0x42>>1].byte.h & 0x0f)
{
case 0x00: /* Drive Status */
{
scd.regs[0x38>>1].byte.h = cdd.status;
break;
}
case 0x01: /* Stop Drive */
{
cdd.status = cdd.loaded ? CD_STOP : NO_DISC;
scd.regs[0x38>>1].w = 0x0000;
scd.regs[0x3a>>1].w = 0x0000;
scd.regs[0x3c>>1].w = 0x0000;
scd.regs[0x3e>>1].w = 0x0000;
scd.regs[0x40>>1].w = 0x000f;
return;
}
case 0x02: /* Read TOC */
{
switch (scd.regs[0x44>>1].byte.l)
{
case 0x00: /* Absolute position (MM:SS:FF) */
{
int lba = cdd.lba + 150;
scd.regs[0x38>>1].w = cdd.status << 8;
scd.regs[0x3a>>1].w = lut_BCD_16[(lba/75)/60];
scd.regs[0x3c>>1].w = lut_BCD_16[(lba/75)%60];
scd.regs[0x3e>>1].w = lut_BCD_16[(lba%75)];
scd.regs[0x40>>1].byte.h = 0x00;
break;
}
case 0x01: /* Track relative position (MM:SS:FF) */
{
int lba = cdd.lba - cdd.toc.tracks[cdd.index].start;
scd.regs[0x38>>1].w = (cdd.status << 8) | 0x01;
scd.regs[0x3a>>1].w = lut_BCD_16[(lba/75)/60];
scd.regs[0x3c>>1].w = lut_BCD_16[(lba/75)%60];
scd.regs[0x3e>>1].w = lut_BCD_16[(lba%75)];
scd.regs[0x40>>1].byte.h = 0x00;
break;
}
case 0x02: /* Current track */
{
scd.regs[0x38>>1].w = (cdd.status << 8) | 0x02;
scd.regs[0x3a>>1].w = (cdd.index < cdd.toc.last) ? lut_BCD_16[cdd.index + 1] : 0x0A0A;
scd.regs[0x3c>>1].w = 0x0000;
scd.regs[0x3e>>1].w = 0x0000;
scd.regs[0x40>>1].byte.h = 0x00;
break;
}
case 0x03: /* Total length (MM:SS:FF) */
{
int lba = cdd.toc.end + 150;
scd.regs[0x38>>1].w = (cdd.status << 8) | 0x03;
scd.regs[0x3a>>1].w = lut_BCD_16[(lba/75)/60];
scd.regs[0x3c>>1].w = lut_BCD_16[(lba/75)%60];
scd.regs[0x3e>>1].w = lut_BCD_16[(lba%75)];
scd.regs[0x40>>1].byte.h = 0x00;
break;
}
case 0x04: /* Number of tracks */
{
scd.regs[0x38>>1].w = (cdd.status << 8) | 0x04;
scd.regs[0x3a>>1].w = 0x0001;
scd.regs[0x3c>>1].w = lut_BCD_16[cdd.toc.last];
scd.regs[0x3e>>1].w = 0x0000;
scd.regs[0x40>>1].byte.h = 0x00;
break;
}
case 0x05: /* Track start (MM:SS:FF) */
{
int track = scd.regs[0x46>>1].byte.h * 10 + scd.regs[0x46>>1].byte.l;
int lba = cdd.toc.tracks[track-1].start + 150;
scd.regs[0x38>>1].w = (cdd.status << 8) | 0x05;
scd.regs[0x3a>>1].w = lut_BCD_16[(lba/75)/60];
scd.regs[0x3c>>1].w = lut_BCD_16[(lba/75)%60];
scd.regs[0x3e>>1].w = lut_BCD_16[(lba%75)];
scd.regs[0x40>>1].byte.h = track % 10;
if (track == 1)
{
/* data track */
scd.regs[0x3e>>1].byte.h |= 0x08;
}
break;
}
default:
{
#ifdef LOG_CDD
error("Unknown Command !!!\n");
#endif
return;
}
}
break;
}
case 0x03: /* Play */
{
/* reset track index */
int index = 0;
/* new LBA position */
int lba = ((scd.regs[0x44>>1].byte.h * 10 + scd.regs[0x44>>1].byte.l) * 60 +
(scd.regs[0x46>>1].byte.h * 10 + scd.regs[0x46>>1].byte.l)) * 75 +
(scd.regs[0x48>>1].byte.h * 10 + scd.regs[0x48>>1].byte.l) - 150;
/* disc access latency */
if (!cdd.latency)
{
/* Fixes a few games hanging during intro 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, Road Avenger & Time Gal need at least 6 interrupts delay */
/* Jeopardy needs at least 9 interrupts delay */
cdd.latency = 9;
}
/* update current LBA */
cdd.lba = lba;
/* update current track index */
while ((cdd.toc.tracks[index].end <= lba) && (index < cdd.toc.last)) index++;
cdd.index = index;
/* track type */
if (index)
{
/* AUDIO track */
scd.regs[0x36>>1].byte.h = 0x00;
}
else
{
/* DATA track */
scd.regs[0x36>>1].byte.h = 0x01;
/* seek to current block */
if (lba < 0) lba = 0;
fseek(cdd.toc.tracks[0].fd, lba * cdd.sectorSize, SEEK_SET);
}
/* update status */
cdd.status = CD_PLAY;
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;
scd.regs[0x3c>>1].w = 0x0000;
scd.regs[0x3e>>1].w = 0x0000;
scd.regs[0x40>>1].byte.h = 0x00;
break;
}
case 0x04: /* Seek */
{
/* reset track index */
int index = 0;
/* new LBA position */
int lba = ((scd.regs[0x44>>1].byte.h * 10 + scd.regs[0x44>>1].byte.l) * 60 +
(scd.regs[0x46>>1].byte.h * 10 + scd.regs[0x46>>1].byte.l)) * 75 +
(scd.regs[0x48>>1].byte.h * 10 + scd.regs[0x48>>1].byte.l) - 150;
/* update current LBA (TODO: add some delay ?) */
cdd.lba = lba;
/* update current track index */
while ((cdd.toc.tracks[index].end <= lba) && (index < cdd.toc.last)) index++;
cdd.index = index;
/* DATA track */
if (!index)
{
/* seek to current block */
if (lba < 0) lba = 0;
fseek(cdd.toc.tracks[0].fd, lba * cdd.sectorSize, SEEK_SET);
}
/* no audio track playing */
scd.regs[0x36>>1].byte.h = 0x01;
/* update status (TODO: figure what is returned in RS1-RS8) */
cdd.status = CD_READY;
scd.regs[0x38>>1].w = CD_SEEK << 8;
scd.regs[0x3a>>1].w = 0x0000;
scd.regs[0x3c>>1].w = 0x0000;
scd.regs[0x3e>>1].w = 0x0000;
scd.regs[0x40>>1].w = ~CD_SEEK & 0x0f;
return;
}
case 0x06: /* Pause */
{
/* no audio track playing */
scd.regs[0x36>>1].byte.h = 0x01;
/* update status (TODO: figure what is returned in RS1-RS8) */
cdd.status = CD_READY;
scd.regs[0x38>>1].w = CD_READY << 8;
scd.regs[0x3a>>1].w = 0x0000;
scd.regs[0x3c>>1].w = 0x0000;
scd.regs[0x3e>>1].w = 0x0000;
scd.regs[0x40>>1].w = ~CD_READY & 0x0f;
return;
}
case 0x07: /* Resume */
{
/* track type */
if (cdd.index)
{
/* AUDIO track */
scd.regs[0x36>>1].byte.h = 0x00;
}
else
{
/* DATA track */
scd.regs[0x36>>1].byte.h = 0x01;
}
/* update status */
cdd.status = CD_PLAY;
scd.regs[0x38>>1].w = (CD_PLAY << 8) | 0x02;
scd.regs[0x3a>>1].w = (cdd.index < cdd.toc.last) ? lut_BCD_16[cdd.index + 1] : 0x0A0A;
scd.regs[0x3c>>1].w = 0x0000;
scd.regs[0x3e>>1].w = 0x0000;
scd.regs[0x40>>1].byte.h = 0x00;
break;
}
case 0x08: /* Forward Scan */
{
cdd.scanOffset = 10;
cdd.status = CD_SCAN;
scd.regs[0x38>>1].w = (CD_SCAN << 8) | 0x02;
scd.regs[0x3a>>1].w = lut_BCD_16[cdd.index+1];
scd.regs[0x3c>>1].w = 0x0000;
scd.regs[0x3e>>1].w = 0x0000;
scd.regs[0x40>>1].byte.h = 0x00;
break;
}
case 0x09: /* Rewind Scan */
{
cdd.scanOffset = -10;
cdd.status = CD_SCAN;
scd.regs[0x38>>1].w = (CD_SCAN << 8) | 0x02;
scd.regs[0x3a>>1].w = lut_BCD_16[cdd.index+1];
scd.regs[0x3c>>1].w = 0x0000;
scd.regs[0x3e>>1].w = 0x0000;
scd.regs[0x40>>1].byte.h = 0x00;
break;
}
case 0x0a: /* ??? (usually sent before first & last CD_PLAY command) */
{
/* RS0-RS8 values taken from Gens */
cdd.status = CD_READY;
scd.regs[0x38>>1].w = CD_READY << 8;
scd.regs[0x3a>>1].w = 0x0000;
scd.regs[0x3c>>1].w = 0x0001;
scd.regs[0x3e>>1].w = 0x0001;
scd.regs[0x40>>1].w = ~(CD_READY + 2) & 0x0f;
return;
}
case 0x0c: /* Close Tray */
{
cdd.status = cdd.loaded ? CD_STOP : NO_DISC;
scd.regs[0x38>>1].w = 0x0000;
scd.regs[0x3a>>1].w = 0x0000;
scd.regs[0x3c>>1].w = 0x0000;
scd.regs[0x3e>>1].w = 0x0000;
scd.regs[0x40>>1].w = 0x000f;
return;
}
case 0x0d: /* Open Tray */
{
/* no audio track playing */
scd.regs[0x36>>1].byte.h = 0x01;
cdd.status = CD_OPEN;
scd.regs[0x38>>1].w = 0x0e00;
scd.regs[0x3a>>1].w = 0x0000;
scd.regs[0x3c>>1].w = 0x0000;
scd.regs[0x3e>>1].w = 0x0000;
scd.regs[0x40>>1].w = 0x0001;
return;
}
default: /* Unknown command */
#ifdef LOG_CDD
error("Unknown CDD Command !!!\n");
#endif
scd.regs[0x38>>1].byte.h = cdd.status;
break;
}
/* only compute checksum when necessary */
scd.regs[0x40>>1].byte.l = ~(scd.regs[0x38>>1].byte.h + scd.regs[0x38>>1].byte.l +
scd.regs[0x3a>>1].byte.h + scd.regs[0x3a>>1].byte.l +
scd.regs[0x3c>>1].byte.h + scd.regs[0x3c>>1].byte.l +
scd.regs[0x3e>>1].byte.h + scd.regs[0x3e>>1].byte.l +
scd.regs[0x40>>1].byte.h) & 0x0f;
}
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