diff --git a/apple2e.cpp b/apple2e.cpp index 348f796..08ba04d 100644 --- a/apple2e.cpp +++ b/apple2e.cpp @@ -266,22 +266,34 @@ struct backed_region : region const region io_region = {"io", 0xC000, 0x100}; -const unsigned char floppy_sectorHeader[21] = { +namespace floppy +{ + +/* +5 1/2" floppy disk images are 35 tracks of 16 sectors of 256 bytes = 143360 bytes +*/ +constexpr int sectorSize = 256; +constexpr int sectorsPerTrack = 16; +constexpr int tracksPerFloppy = 35; + +const unsigned char sectorHeader[21] = { 0xD5, 0xAA, 0x96, 0xFF, 0xFE, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xDE, 0xAA, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xD5, 0xAA, 0xAD }; -const unsigned char floppy_doSector[16] = { + +const unsigned char doSectorSkew[16] = { 0x0, 0x7, 0xE, 0x6, 0xD, 0x5, 0xC, 0x4, 0xB, 0x3, 0xA, 0x2, 0x9, 0x1, 0x8, 0xF }; -const unsigned char floppy_poSector[16] = { +const unsigned char poSectorSkew[16] = { 0x0, 0x8, 0x1, 0x9, 0x2, 0xA, 0x3, 0xB, 0x4, 0xC, 0x5, 0xD, 0x6, 0xE, 0x7, 0xF }; -const unsigned char floppy_sectorFooter[48] = { + +const unsigned char sectorFooter[48] = { 0xDE, 0xAA, 0xEB, 0xFF, 0xEB, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF }; -const unsigned char floppy_6BitsToBytes[0x40] = { +const unsigned char SixBitsToBytes[0x40] = { 0x96, 0x97, 0x9A, 0x9B, 0x9D, 0x9E, 0x9F, 0xA6, 0xA7, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7, 0xB9, 0xBA, 0xBB, 0xBC, @@ -291,9 +303,9 @@ const unsigned char floppy_6BitsToBytes[0x40] = { 0xED, 0xEE, 0xEF, 0xF2, 0xF3, 0xF4, 0xF5, 0xF6, 0xF7, 0xF9, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE, 0xFF }; -constexpr size_t floppy_trackGapSize = 64; +constexpr size_t trackGapSize = 64; constexpr size_t nybblizedSectorSize = 21 + 343 + 48; -constexpr size_t nybblizedTrackSize = floppy_trackGapSize + 16 * nybblizedSectorSize; +constexpr size_t nybblizedTrackSize = trackGapSize + sectorsPerTrack * nybblizedSectorSize; void nybblizeSector(int trackIndex, int sectorIndex, const uint8_t *sectorBytes, uint8_t *sectorNybblized) { @@ -301,7 +313,7 @@ void nybblizeSector(int trackIndex, int sectorIndex, const uint8_t *sectorBytes, uint8_t *p = sectorNybblized; - memcpy(p, floppy_sectorHeader, sizeof(floppy_sectorHeader)); // Set up the sectorIndex header + memcpy(p, sectorHeader, sizeof(sectorHeader)); // Set up the sectorIndex header p[5] = ((trackIndex >> 1) & 0x55) | 0xAA; p[6] = (trackIndex & 0x55) | 0xAA; @@ -339,16 +351,16 @@ void nybblizeSector(int trackIndex, int sectorIndex, const uint8_t *sectorBytes, // Using a lookup table, convert the 6-bit bytes into disk bytes. for(int i=0; i<343; i++) - p[i] = floppy_6BitsToBytes[p[i] >> 2]; + p[i] = SixBitsToBytes[p[i] >> 2]; p += 343; // Done with the nybblization, now for the epilogue... - memcpy(p, floppy_sectorFooter, sizeof(floppy_sectorFooter)); + memcpy(p, sectorFooter, sizeof(sectorFooter)); // p += 48; } -void floppy_NybblizeImage(const unsigned char *floppyByteImage, unsigned char *nybblizedImage, const unsigned char *skew) +bool nybblizeImage(FILE *floppyImageFile, unsigned char *nybblizedImage, const unsigned char *skew) { // Format of a sector is header (23) + nybbles (343) + footer (30) = 396 // (short by 20 bytes of 416 [413 if 48 byte header is one time only]) @@ -359,16 +371,32 @@ void floppy_NybblizeImage(const unsigned char *floppyByteImage, unsigned char *n { unsigned char *nybblizedTrack = nybblizedImage + trackIndex * nybblizedTrackSize; - memset(nybblizedTrack, 0xFF, floppy_trackGapSize); // Write gap 1, 64 bytes (self-sync) + memset(nybblizedTrack, 0xFF, trackGapSize); // Write gap 1, 64 bytes (self-sync) for(unsigned char sectorIndex = 0; sectorIndex < 16; sectorIndex++) { - const unsigned char * sectorBytes = floppyByteImage + (skew[sectorIndex] * 256) + (trackIndex * 256 * 16); + long sectorOffset = (skew[sectorIndex] + trackIndex * sectorsPerTrack) * sectorSize; + int seeked = fseek(floppyImageFile, sectorOffset, SEEK_SET); + if(seeked == -1) { + fprintf(stderr, "failed to seek to sector in floppy disk image\n"); + return false; + } + + unsigned char sectorBytes[256]; + size_t wasRead = fread(sectorBytes, 1, sectorSize, floppyImageFile); + if(wasRead != sectorSize) { + fprintf(stderr, "failed to read sector from floppy disk image\n"); + return false; + } + nybblizeSector(trackIndex, sectorIndex, sectorBytes, nybblizedTrack + sectorIndex * nybblizedSectorSize); } } + return true; } +}; + // XXX readonly at this time struct DISKIIboard : board_base { @@ -404,10 +432,10 @@ struct DISKIIboard : board_base backed_region rom_C600 = {"rom_C600", 0xC600, 0x0100, ROM, nullptr, [&]{return true;}}; - unsigned char *floppy_image[2]; // [143360]; unsigned char *floppy_nybblized[2]; // [232960]; const unsigned int bytes_per_nybblized_track = 6656; bool floppy_present[2]; + FILE *floppyImageFiles[2] = {nullptr, nullptr}; int drive_selected = 0; bool drive_motor_enabled[2]; @@ -421,19 +449,36 @@ struct DISKIIboard : board_base void set_floppy(int number, const char *name) // number 0 or 1; name = NULL to eject { floppy_present[number] = false; + if(name) { - if(!read_blob(name, floppy_image[number], 143360 /*sizeof(floppy_image[0])*/)) - throw "Couldn't read floppy"; - - floppy_present[number] = true; - const unsigned char *skew; - if(strcmp(name + strlen(name) - 3, ".po") == 0) { - printf("ProDOS floppy\n"); - skew = floppy_poSector; - } else { - skew = floppy_doSector; + if(floppyImageFiles[number]) { + fclose(floppyImageFiles[number]); + } + + floppyImageFiles[number] = fopen(name, "rb"); + + if(!floppyImageFiles[number]) { + + fprintf(stderr, "Couldn't open floppy disk image \"%s\"\n", name); + + } else { + + const unsigned char *skew; + if(strcmp(name + strlen(name) - 3, ".po") == 0) { + printf("ProDOS floppy\n"); + skew = floppy::poSectorSkew; + } else { + skew = floppy::doSectorSkew; + } + + bool success = floppy::nybblizeImage(floppyImageFiles[number], floppy_nybblized[number], skew); + if(!success) { + floppyImageFiles[number] = nullptr; + fprintf(stderr, "unexpected failure reading sector from disk \"%s\"\n", name); + } + + floppy_present[number] = true; } - floppy_NybblizeImage(floppy_image[number], floppy_nybblized[number], skew); } } @@ -445,10 +490,6 @@ struct DISKIIboard : board_base { std::copy(diskII_rom, diskII_rom + 0x100, rom_C600.memory.begin()); if(floppy0_name) { - floppy_image[0] = new (std::nothrow) unsigned char[143360]; - if(!floppy_image[0]) { - throw "failed to allocate floppy_image[0]"; - } floppy_nybblized[0] = new (std::nothrow) unsigned char[232960]; if(!floppy_nybblized[0]) { throw "failed to allocate floppy_nybblized[0]"; @@ -456,10 +497,6 @@ struct DISKIIboard : board_base set_floppy(0, floppy0_name); } if(floppy1_name) { - floppy_image[1] = new (std::nothrow) unsigned char[143360]; - if(!floppy_image[1]) { - throw "failed to allocate floppy_image[1]"; - } floppy_nybblized[1] = new (std::nothrow) unsigned char[232960]; if(!floppy_nybblized[1]) { throw "failed to allocate floppy_nybblized[1]"; @@ -489,9 +526,11 @@ struct DISKIIboard : board_base if(state == 1) { // turn stepper motor phase on if(head_stepper_most_recent_phase == (((phase - 1) + 4) % 4)) { // stepping up track_number = min(track_number + 1, 70); + // XXX load track if(debug & DEBUG_FLOPPY) printf("track number now %d\n", track_number); } else if(head_stepper_most_recent_phase == ((phase + 1) % 4)) { // stepping down track_number = max(0, track_number - 1); + // XXX load track if(debug & DEBUG_FLOPPY) printf("track number now %d\n", track_number); } else if(head_stepper_most_recent_phase == phase) { // unexpected condition if(debug & DEBUG_FLOPPY) printf("track head stepper no change\n");