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https://github.com/bradgrantham/apple2e.git
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use a function to nybblize sector
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ba52591064
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166
apple2e.cpp
166
apple2e.cpp
@ -266,101 +266,107 @@ struct backed_region : region
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const region io_region = {"io", 0xC000, 0x100};
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unsigned char floppy_header[21] = {
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const unsigned char floppy_sectorHeader[21] = {
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0xD5, 0xAA, 0x96, 0xFF, 0xFE, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0xDE, 0xAA, 0xFF, 0xFF, 0xFF,
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0x00, 0x00, 0x00, 0xDE, 0xAA, 0xFF, 0xFF, 0xFF,
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0xFF, 0xFF, 0xD5, 0xAA, 0xAD };
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unsigned char floppy_doSector[16] = {
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const unsigned char floppy_doSector[16] = {
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0x0, 0x7, 0xE, 0x6, 0xD, 0x5, 0xC, 0x4, 0xB, 0x3, 0xA, 0x2, 0x9, 0x1, 0x8, 0xF };
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unsigned char floppy_poSector[16] = {
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const unsigned char floppy_poSector[16] = {
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0x0, 0x8, 0x1, 0x9, 0x2, 0xA, 0x3, 0xB, 0x4, 0xC, 0x5, 0xD, 0x6, 0xE, 0x7, 0xF };
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const unsigned char floppy_sectorFooter[48] = {
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0xDE, 0xAA, 0xEB, 0xFF, 0xEB, 0xFF, 0xFF, 0xFF,
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0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
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0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
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0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
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0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
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0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
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const unsigned char floppy_6BitsToBytes[0x40] = {
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0x96, 0x97, 0x9A, 0x9B, 0x9D, 0x9E, 0x9F, 0xA6,
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0xA7, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF, 0xB2, 0xB3,
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0xB4, 0xB5, 0xB6, 0xB7, 0xB9, 0xBA, 0xBB, 0xBC,
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0xBD, 0xBE, 0xBF, 0xCB, 0xCD, 0xCE, 0xCF, 0xD3,
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0xD6, 0xD7, 0xD9, 0xDA, 0xDB, 0xDC, 0xDD, 0xDE,
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0xDF, 0xE5, 0xE6, 0xE7, 0xE9, 0xEA, 0xEB, 0xEC,
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0xED, 0xEE, 0xEF, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6,
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0xF7, 0xF9, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE, 0xFF };
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void floppy_NybblizeImage(const unsigned char *image, unsigned char *nybblized, unsigned char *skew)
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constexpr size_t floppy_trackGapSize = 64;
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constexpr size_t nybblizedSectorSize = 21 + 343 + 48;
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constexpr size_t nybblizedTrackSize = floppy_trackGapSize + 16 * nybblizedSectorSize;
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void nybblizeSector(int trackIndex, int sectorIndex, const uint8_t *sectorBytes, uint8_t *sectorNybblized)
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{
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// Format of a sector is header (23) + nybbles (343) + footer (30) = 396
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// (short by 20 bytes of 416 [413 if 48 byte header is one time only])
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// hdr (21) + nybbles (343) + footer (48) = 412 bytes per sector
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// (not incl. 64 byte track marker)
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memset(sectorNybblized, 0xFF, nybblizedSectorSize); // Doesn't matter if 00s or FFs...
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static unsigned char footer[48] = {
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0xDE, 0xAA, 0xEB, 0xFF, 0xEB, 0xFF, 0xFF, 0xFF,
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0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
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0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
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0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
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0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
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0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
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uint8_t *p = sectorNybblized;
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static unsigned char diskbyte[0x40] = {
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0x96, 0x97, 0x9A, 0x9B, 0x9D, 0x9E, 0x9F, 0xA6,
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0xA7, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF, 0xB2, 0xB3,
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0xB4, 0xB5, 0xB6, 0xB7, 0xB9, 0xBA, 0xBB, 0xBC,
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0xBD, 0xBE, 0xBF, 0xCB, 0xCD, 0xCE, 0xCF, 0xD3,
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0xD6, 0xD7, 0xD9, 0xDA, 0xDB, 0xDC, 0xDD, 0xDE,
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0xDF, 0xE5, 0xE6, 0xE7, 0xE9, 0xEA, 0xEB, 0xEC,
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0xED, 0xEE, 0xEF, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6,
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0xF7, 0xF9, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE, 0xFF };
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memcpy(p, floppy_sectorHeader, sizeof(floppy_sectorHeader)); // Set up the sectorIndex header
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memset(nybblized, 0xFF, 232960); // Doesn't matter if 00s or FFs...
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p[5] = ((trackIndex >> 1) & 0x55) | 0xAA;
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p[6] = (trackIndex & 0x55) | 0xAA;
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p[7] = ((sectorIndex >> 1) & 0x55) | 0xAA;
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p[8] = (sectorIndex & 0x55) | 0xAA;
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p[9] = (((trackIndex ^ sectorIndex ^ 0xFE) >> 1) & 0x55) | 0xAA;
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p[10] = ((trackIndex ^ sectorIndex ^ 0xFE) & 0x55) | 0xAA;
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unsigned char *p = nybblized;
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p += 21;
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for(unsigned char trk=0; trk<35; trk++)
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{
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memset(p, 0xFF, 64); // Write gap 1, 64 bytes (self-sync)
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p += 64;
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// Convert the 256 8-bit bytes into 342 6-bit bytes.
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for(unsigned char sector=0; sector<16; sector++)
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{
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memcpy(p, floppy_header, 21); // Set up the sector header
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for(int i=0; i<0x56; i++)
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{
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p[i] = ((sectorBytes[(i + 0xAC) & 0xFF] & 0x01) << 7)
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| ((sectorBytes[(i + 0xAC) & 0xFF] & 0x02) << 5)
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| ((sectorBytes[(i + 0x56) & 0xFF] & 0x01) << 5)
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| ((sectorBytes[(i + 0x56) & 0xFF] & 0x02) << 3)
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| ((sectorBytes[(i + 0x00) & 0xFF] & 0x01) << 3)
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| ((sectorBytes[(i + 0x00) & 0xFF] & 0x02) << 1);
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}
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p[5] = ((trk >> 1) & 0x55) | 0xAA;
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p[6] = (trk & 0x55) | 0xAA;
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p[7] = ((sector >> 1) & 0x55) | 0xAA;
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p[8] = (sector & 0x55) | 0xAA;
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p[9] = (((trk ^ sector ^ 0xFE) >> 1) & 0x55) | 0xAA;
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p[10] = ((trk ^ sector ^ 0xFE) & 0x55) | 0xAA;
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p[0x54] &= 0x3F;
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p[0x55] &= 0x3F;
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memcpy(p + 0x56, sectorBytes, 256);
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p += 21;
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const unsigned char * bytes = image;
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// XOR the data block with itself, offset by one byte,
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// creating a 343rd byte which is used as a cheksum.
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bytes += (skew[sector] * 256) + (trk * 256 * 16);
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p[342] = 0x00;
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// Convert the 256 8-bit bytes into 342 6-bit bytes.
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for(int i=342; i>0; i--)
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p[i] = p[i] ^ p[i - 1];
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for(int i=0; i<0x56; i++)
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{
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p[i] = ((bytes[(i + 0xAC) & 0xFF] & 0x01) << 7)
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| ((bytes[(i + 0xAC) & 0xFF] & 0x02) << 5)
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| ((bytes[(i + 0x56) & 0xFF] & 0x01) << 5)
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| ((bytes[(i + 0x56) & 0xFF] & 0x02) << 3)
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| ((bytes[(i + 0x00) & 0xFF] & 0x01) << 3)
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| ((bytes[(i + 0x00) & 0xFF] & 0x02) << 1);
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}
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// Using a lookup table, convert the 6-bit bytes into disk bytes.
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p[0x54] &= 0x3F;
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p[0x55] &= 0x3F;
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memcpy(p + 0x56, bytes, 256);
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for(int i=0; i<343; i++)
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p[i] = floppy_6BitsToBytes[p[i] >> 2];
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p += 343;
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// XOR the data block with itself, offset by one byte,
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// creating a 343rd byte which is used as a cheksum.
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// Done with the nybblization, now for the epilogue...
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p[342] = 0x00;
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memcpy(p, floppy_sectorFooter, sizeof(floppy_sectorFooter));
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// p += 48;
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}
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for(int i=342; i>0; i--)
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p[i] = p[i] ^ p[i - 1];
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void floppy_NybblizeImage(const unsigned char *floppyByteImage, unsigned char *nybblizedImage, const unsigned char *skew)
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{
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// Format of a sector is header (23) + nybbles (343) + footer (30) = 396
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// (short by 20 bytes of 416 [413 if 48 byte header is one time only])
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// hdr (21) + nybbles (343) + footer (48) = 412 bytes per sector
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// (not incl. 64 byte track marker)
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// Using a lookup table, convert the 6-bit bytes into disk bytes.
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for(unsigned char trackIndex = 0; trackIndex < 35; trackIndex++)
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{
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unsigned char *nybblizedTrack = nybblizedImage + trackIndex * nybblizedTrackSize;
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for(int i=0; i<343; i++)
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p[i] = diskbyte[p[i] >> 2];
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p += 343;
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memset(nybblizedTrack, 0xFF, floppy_trackGapSize); // Write gap 1, 64 bytes (self-sync)
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// Done with the nybblization, now for the epilogue...
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memcpy(p, footer, 48);
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p += 48;
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}
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}
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for(unsigned char sectorIndex = 0; sectorIndex < 16; sectorIndex++)
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{
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const unsigned char * sectorBytes = floppyByteImage + (skew[sectorIndex] * 256) + (trackIndex * 256 * 16);
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nybblizeSector(trackIndex, sectorIndex, sectorBytes, nybblizedTrack + sectorIndex * nybblizedSectorSize);
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}
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}
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}
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// XXX readonly at this time
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@ -420,13 +426,13 @@ struct DISKIIboard : board_base
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throw "Couldn't read floppy";
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floppy_present[number] = true;
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unsigned char *skew;
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const unsigned char *skew;
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if(strcmp(name + strlen(name) - 3, ".po") == 0) {
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printf("ProDOS floppy\n");
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skew = floppy_poSector;
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}
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else
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} else {
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skew = floppy_doSector;
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}
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floppy_NybblizeImage(floppy_image[number], floppy_nybblized[number], skew);
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}
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}
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@ -439,26 +445,26 @@ struct DISKIIboard : board_base
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{
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std::copy(diskII_rom, diskII_rom + 0x100, rom_C600.memory.begin());
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if(floppy0_name) {
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floppy_image[0] = new unsigned char[143360];
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floppy_image[0] = new (std::nothrow) unsigned char[143360];
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if(!floppy_image[0]) {
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throw "failed to allocate floppy_image[0]";
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}
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floppy_nybblized[0] = new unsigned char[232960];
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floppy_nybblized[0] = new (std::nothrow) unsigned char[232960];
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if(!floppy_nybblized[0]) {
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throw "failed to allocate floppy_nybblized[0]";
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}
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set_floppy(0, floppy0_name);
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set_floppy(0, floppy0_name);
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}
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if(floppy1_name) {
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floppy_image[1] = new unsigned char[143360];
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floppy_image[1] = new (std::nothrow) unsigned char[143360];
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if(!floppy_image[1]) {
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throw "failed to allocate floppy_image[1]";
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}
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floppy_nybblized[1] = new unsigned char[232960];
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floppy_nybblized[1] = new (std::nothrow) unsigned char[232960];
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if(!floppy_nybblized[1]) {
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throw "failed to allocate floppy_nybblized[1]";
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}
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set_floppy(1, floppy1_name);
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set_floppy(1, floppy1_name);
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}
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}
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