112 lines
3.3 KiB
C
112 lines
3.3 KiB
C
/*
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libpsxav: MDEC video + SPU/XA-ADPCM audio library
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Copyright (c) 2019, 2020 Adrian "asie" Siekierka
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Copyright (c) 2019 Ben "GreaseMonkey" Russell
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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*/
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#include <stdint.h>
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#include <string.h>
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#include "libpsxav.h"
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#define EDC_CRC32_POLYNOMIAL 0xD8018001
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static uint32_t edc_crc32(uint8_t *data, int length) {
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uint32_t edc = 0;
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for (int i = 0; i < length; i++) {
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edc ^= 0xFF & (uint32_t)data[i];
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for (int j = 0; j < 8; j++)
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edc = (edc >> 1) ^ (EDC_CRC32_POLYNOMIAL * (edc & 0x1));
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}
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return edc;
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}
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#define TO_BCD(x) ((x) + ((x) / 10) * 6)
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void psx_cdrom_init_xa_subheader(psx_cdrom_sector_xa_subheader_t *subheader, psx_cdrom_sector_type_t type) {
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memset(subheader, 0, sizeof(psx_cdrom_sector_xa_subheader_t) * 2);
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subheader->submode = PSX_CDROM_SECTOR_XA_SUBMODE_DATA;
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if (type == PSX_CDROM_SECTOR_TYPE_MODE2_FORM2)
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subheader->submode |= PSX_CDROM_SECTOR_XA_SUBMODE_FORM2;
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memcpy(subheader + 1, subheader, sizeof(psx_cdrom_sector_xa_subheader_t));
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}
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void psx_cdrom_init_sector(psx_cdrom_sector_t *sector, int lba, psx_cdrom_sector_type_t type) {
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// Sync sequence
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memset(sector->mode1.sync + 1, 0xff, 10);
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sector->mode1.sync[0x0] = 0x00;
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sector->mode1.sync[0xB] = 0x00;
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// Timecode
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lba += 150;
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sector->mode1.header.minute = TO_BCD(lba / 4500);
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sector->mode1.header.second = TO_BCD((lba / 75) % 60);
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sector->mode1.header.sector = TO_BCD(lba % 75);
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// Mode
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if (type == PSX_CDROM_SECTOR_TYPE_MODE1) {
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sector->mode1.header.mode = 0x01;
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} else {
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sector->mode2.header.mode = 0x02;
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psx_cdrom_init_xa_subheader(sector->mode2.subheader, type);
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}
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}
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void psx_cdrom_calculate_checksums(psx_cdrom_sector_t *sector, psx_cdrom_sector_type_t type) {
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uint8_t *data = (uint8_t *)sector;
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uint32_t edc;
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switch (type) {
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case PSX_CDROM_SECTOR_TYPE_MODE1:
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edc = edc_crc32(data, 0x810);
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data[0x810] = (uint8_t)(edc);
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data[0x811] = (uint8_t)(edc >> 8);
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data[0x812] = (uint8_t)(edc >> 16);
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data[0x813] = (uint8_t)(edc >> 24);
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memset(sector + 0x814, 0, 8);
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// TODO: ECC
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break;
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case PSX_CDROM_SECTOR_TYPE_MODE2_FORM1:
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edc = edc_crc32(data + 0x10, 0x808);
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data[0x818] = (uint8_t)(edc);
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data[0x819] = (uint8_t)(edc >> 8);
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data[0x81A] = (uint8_t)(edc >> 16);
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data[0x81B] = (uint8_t)(edc >> 24);
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// TODO: ECC
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break;
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case PSX_CDROM_SECTOR_TYPE_MODE2_FORM2:
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edc = edc_crc32(data + 0x10, 0x91C);
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data[0x92C] = (uint8_t)(edc);
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data[0x92D] = (uint8_t)(edc >> 8);
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data[0x92E] = (uint8_t)(edc >> 16);
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data[0x92F] = (uint8_t)(edc >> 24);
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break;
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}
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}
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