src/wd279x.c

Wed, 29 Dec 2010 03:27:35 +0000

author
Philip Pemberton <philpem@philpem.me.uk>
date
Wed, 29 Dec 2010 03:27:35 +0000
changeset 77
e7898cbae0c6
parent 73
05ef5f3c5246
parent 76
2ef98ea1e944
child 79
674226015c8a
permissions
-rw-r--r--

discard head, need to merge some stuff back in later

philpem@48 1 #include <stdint.h>
philpem@48 2 #include <stdbool.h>
philpem@49 3 #include <malloc.h>
philpem@53 4 #include "musashi/m68k.h"
philpem@48 5 #include "wd279x.h"
philpem@48 6
philpem@73 7 #ifndef WD279X_DEBUG
philpem@71 8 #define NDEBUG
philpem@73 9 #endif
philpem@71 10 #include "utils.h"
philpem@71 11
philpem@48 12 /// WD2797 command constants
philpem@48 13 enum {
philpem@48 14 CMD_MASK = 0xF0, ///< Bit mask to detect command bits
philpem@48 15 CMD_RESTORE = 0x00, ///< Restore (recalibrate, seek to track 0)
philpem@48 16 CMD_SEEK = 0x10, ///< Seek to given track
philpem@48 17 CMD_STEP = 0x20, ///< Step
philpem@48 18 CMD_STEP_TU = 0x30, ///< Step and update track register
philpem@48 19 CMD_STEPIN = 0x40, ///< Step In
philpem@48 20 CMD_STEPIN_TU = 0x50, ///< Step In and update track register
philpem@48 21 CMD_STEPOUT = 0x60, ///< Step Out
philpem@48 22 CMD_STEPOUT_TU = 0x70, ///< Step Out and update track register
philpem@48 23 CMD_READ_SECTOR = 0x80, ///< Read Sector
philpem@48 24 CMD_READ_SECTOR_MULTI = 0x90, ///< Read Multiple Sectors
philpem@48 25 CMD_WRITE_SECTOR = 0xA0, ///< Write Sector
philpem@48 26 CMD_WRITE_SECTOR_MULTI = 0xB0, ///< Write Multiple Sectors
philpem@48 27 CMD_READ_ADDRESS = 0xC0, ///< Read Address (IDAM contents)
philpem@48 28 CMD_FORCE_INTERRUPT = 0xD0, ///< Force Interrupt
philpem@48 29 CMD_READ_TRACK = 0xE0, ///< Read Track
philpem@48 30 CMD_FORMAT_TRACK = 0xF0 ///< Format Track
philpem@48 31 };
philpem@48 32
philpem@48 33
philpem@49 34 void wd2797_init(WD2797_CTX *ctx)
philpem@48 35 {
philpem@48 36 // track, head and sector unknown
philpem@49 37 ctx->track = ctx->head = ctx->sector = 0;
philpem@48 38
philpem@49 39 // no IRQ pending
philpem@49 40 ctx->irql = ctx->irqe = false;
philpem@48 41
philpem@48 42 // no data available
philpem@49 43 ctx->data_pos = ctx->data_len = 0;
philpem@49 44 ctx->data = NULL;
philpem@49 45
philpem@49 46 // Status register clear, not busy
philpem@49 47 ctx->status = 0;
philpem@49 48
philpem@49 49 // Clear data register
philpem@49 50 ctx->data_reg = 0;
philpem@49 51
philpem@49 52 // Last step direction
philpem@49 53 ctx->last_step_dir = -1;
philpem@48 54
philpem@48 55 // No disc image loaded
philpem@48 56 ctx->disc_image = NULL;
philpem@49 57 ctx->geom_secsz = ctx->geom_spt = ctx->geom_heads = ctx->geom_tracks = 0;
philpem@48 58 }
philpem@48 59
philpem@48 60
philpem@49 61 void wd2797_reset(WD2797_CTX *ctx)
philpem@49 62 {
philpem@49 63 // track, head and sector unknown
philpem@49 64 ctx->track = ctx->head = ctx->sector = 0;
philpem@49 65
philpem@49 66 // no IRQ pending
philpem@49 67 ctx->irql = ctx->irqe = false;
philpem@49 68
philpem@49 69 // no data available
philpem@49 70 ctx->data_pos = ctx->data_len = 0;
philpem@49 71
philpem@49 72 // Status register clear, not busy
philpem@49 73 ctx->status = 0;
philpem@49 74
philpem@49 75 // Clear data register
philpem@49 76 ctx->data_reg = 0;
philpem@49 77
philpem@49 78 // Last step direction
philpem@49 79 ctx->last_step_dir = -1;
philpem@49 80 }
philpem@49 81
philpem@49 82
philpem@49 83 void wd2797_done(WD2797_CTX *ctx)
philpem@49 84 {
philpem@49 85 // Reset the WD2797
philpem@49 86 wd2797_reset(ctx);
philpem@49 87
philpem@49 88 // Free any allocated memory
philpem@49 89 if (ctx->data) {
philpem@49 90 free(ctx->data);
philpem@49 91 ctx->data = NULL;
philpem@49 92 }
philpem@49 93 }
philpem@49 94
philpem@49 95
philpem@49 96 bool wd2797_get_irq(WD2797_CTX *ctx)
philpem@48 97 {
philpem@48 98 // If an IRQ is pending, clear it and return true, otherwise return false
philpem@48 99 if (ctx->irqe) {
philpem@48 100 ctx->irqe = false;
philpem@48 101 return true;
philpem@48 102 } else {
philpem@48 103 return false;
philpem@48 104 }
philpem@48 105 }
philpem@48 106
philpem@48 107
philpem@49 108 bool wd2797_get_drq(WD2797_CTX *ctx)
philpem@48 109 {
philpem@48 110 return (ctx->data_pos < ctx->data_len);
philpem@48 111 }
philpem@48 112
philpem@48 113
philpem@49 114 WD2797_ERR wd2797_load(WD2797_CTX *ctx, FILE *fp, int secsz, int spt, int heads)
philpem@49 115 {
philpem@49 116 size_t filesize;
philpem@49 117
philpem@49 118 // Start by finding out how big the image file is
philpem@49 119 fseek(fp, 0, SEEK_END);
philpem@49 120 filesize = ftell(fp);
philpem@49 121 fseek(fp, 0, SEEK_SET);
philpem@49 122
philpem@49 123 // Now figure out how many tracks it contains
philpem@49 124 int tracks = filesize / secsz / spt / heads;
philpem@49 125 // Confirm...
philpem@49 126 if (tracks < 1) {
philpem@49 127 return WD2797_ERR_BAD_GEOM;
philpem@49 128 }
philpem@49 129
philpem@49 130 // Allocate enough memory to store one disc track
philpem@49 131 if (ctx->data) {
philpem@49 132 free(ctx->data);
philpem@49 133 }
philpem@49 134 ctx->data = malloc(secsz * spt);
philpem@49 135 if (!ctx->data)
philpem@49 136 return WD2797_ERR_NO_MEMORY;
philpem@49 137
philpem@49 138 // Load the image and the geometry data
philpem@49 139 ctx->disc_image = fp;
philpem@49 140 ctx->geom_tracks = tracks;
philpem@49 141 ctx->geom_secsz = secsz;
philpem@49 142 ctx->geom_heads = heads;
philpem@49 143 ctx->geom_spt = spt;
philpem@49 144
philpem@49 145 return WD2797_ERR_OK;
philpem@49 146 }
philpem@49 147
philpem@49 148
philpem@49 149 void wd2797_unload(WD2797_CTX *ctx)
philpem@49 150 {
philpem@49 151 // Free memory buffer
philpem@49 152 if (ctx->data) {
philpem@49 153 free(ctx->data);
philpem@49 154 ctx->data = NULL;
philpem@49 155 }
philpem@49 156
philpem@49 157 // Clear file pointer
philpem@49 158 ctx->disc_image = NULL;
philpem@49 159
philpem@49 160 // Clear the disc geometry
philpem@49 161 ctx->geom_tracks = ctx->geom_secsz = ctx->geom_spt = ctx->geom_heads = 0;
philpem@49 162 }
philpem@49 163
philpem@49 164
philpem@49 165 uint8_t wd2797_read_reg(WD2797_CTX *ctx, uint8_t addr)
philpem@48 166 {
philpem@48 167 uint8_t temp = 0;
philpem@48 168
philpem@48 169 switch (addr & 0x03) {
philpem@49 170 case WD2797_REG_STATUS: // Status register
philpem@48 171 // Read from status register clears IRQ
philpem@48 172 ctx->irql = false;
philpem@53 173 ctx->irqe = false;
philpem@48 174
philpem@48 175 // Get current status flags (set by last command)
philpem@48 176 // DRQ bit
philpem@53 177 if (ctx->cmd_has_drq) {
philpem@53 178 temp = ctx->status & ~0x03;
philpem@48 179 temp |= (ctx->data_pos < ctx->data_len) ? 0x02 : 0x00;
philpem@71 180 LOG("\tWDFDC rd sr, has drq, pos=%lu len=%lu, sr=0x%02X", ctx->data_pos, ctx->data_len, temp);
philpem@53 181 } else {
philpem@53 182 temp = ctx->status & ~0x01;
philpem@53 183 }
philpem@48 184 // FDC is busy if there is still data in the buffer
philpem@48 185 temp |= (ctx->data_pos < ctx->data_len) ? 0x01 : 0x00; // if data in buffer, then DMA hasn't copied it yet, and we're still busy!
philpem@49 186 // TODO: also if seek delay / read delay hasn't passed (but that's for later)
philpem@48 187 return temp;
philpem@48 188
philpem@49 189 case WD2797_REG_TRACK: // Track register
philpem@48 190 return ctx->track;
philpem@48 191
philpem@49 192 case WD2797_REG_SECTOR: // Sector register
philpem@48 193 return ctx->sector;
philpem@48 194
philpem@49 195 case WD2797_REG_DATA: // Data register
philpem@48 196 // If there's data in the buffer, return it. Otherwise return 0xFF.
philpem@48 197 if (ctx->data_pos < ctx->data_len) {
philpem@53 198 // set IRQ if this is the last data byte
philpem@53 199 if (ctx->data_pos == (ctx->data_len-1)) {
philpem@53 200 // Set IRQ only if IRQL has been cleared (no pending IRQs)
philpem@53 201 ctx->irqe = ctx->irql ? ctx->irqe : true;
philpem@53 202 ctx->irql = true;
philpem@53 203 }
philpem@48 204 // return data byte and increment pointer
philpem@48 205 return ctx->data[ctx->data_pos++];
philpem@48 206 } else {
philpem@53 207 // command finished
philpem@48 208 return 0xff;
philpem@48 209 }
philpem@48 210
philpem@48 211 default:
philpem@48 212 // shut up annoying compilers which don't recognise unreachable code when they see it
philpem@48 213 // (here's looking at you, gcc!)
philpem@48 214 return 0xff;
philpem@48 215 }
philpem@48 216 }
philpem@48 217
philpem@48 218
philpem@49 219 void wd2797_write_reg(WD2797_CTX *ctx, uint8_t addr, uint8_t val)
philpem@48 220 {
philpem@48 221 uint8_t cmd = val & CMD_MASK;
philpem@48 222 size_t lba;
philpem@48 223 bool is_type1 = false;
philpem@49 224 int temp;
philpem@48 225
philpem@53 226 m68k_end_timeslice();
philpem@53 227
philpem@48 228 switch (addr) {
philpem@49 229 case WD2797_REG_COMMAND: // Command register
philpem@48 230 // write to command register clears interrupt request
philpem@48 231 ctx->irql = false;
philpem@48 232
philpem@48 233 // Is the drive ready?
philpem@48 234 if (ctx->disc_image == NULL) {
philpem@48 235 // No disc image, thus the drive is busy.
philpem@48 236 ctx->status = 0x80;
philpem@48 237 return;
philpem@48 238 }
philpem@48 239
philpem@48 240 // Handle Type 1 commands
philpem@48 241 switch (cmd) {
philpem@48 242 case CMD_RESTORE:
philpem@48 243 // Restore. Set track to 0 and throw an IRQ.
philpem@48 244 is_type1 = true;
philpem@48 245 ctx->track = 0;
philpem@48 246 break;
philpem@48 247
philpem@48 248 case CMD_SEEK:
philpem@48 249 // Seek. Seek to the track specced in the Data Register.
philpem@48 250 is_type1 = true;
philpem@48 251 if (ctx->data_reg < ctx->geom_tracks) {
philpem@48 252 ctx->track = ctx->data_reg;
philpem@48 253 } else {
philpem@48 254 // Seek error. :(
philpem@48 255 ctx->status = 0x10;
philpem@48 256 }
philpem@48 257
philpem@48 258 case CMD_STEP:
philpem@48 259 // TODO! deal with trk0!
philpem@48 260 // Need to keep a copy of the track register; when it hits 0, set the TRK0 flag.
philpem@48 261 is_type1 = true;
philpem@48 262 break;
philpem@48 263
philpem@48 264 case CMD_STEPIN:
philpem@48 265 case CMD_STEPOUT:
philpem@48 266 // TODO! deal with trk0!
philpem@48 267 // Need to keep a copy of the track register; when it hits 0, set the TRK0 flag.
philpem@48 268 if (cmd == CMD_STEPIN) {
philpem@48 269 ctx->last_step_dir = 1;
philpem@48 270 } else {
philpem@48 271 ctx->last_step_dir = -1;
philpem@48 272 }
philpem@48 273 is_type1 = true;
philpem@48 274 break;
philpem@48 275
philpem@48 276 case CMD_STEP_TU:
philpem@48 277 case CMD_STEPIN_TU:
philpem@48 278 case CMD_STEPOUT_TU:
philpem@48 279 // if this is a Step In or Step Out cmd, set the step-direction
philpem@48 280 if (cmd == CMD_STEPIN_TU) {
philpem@48 281 ctx->last_step_dir = 1;
philpem@48 282 } else if (cmd == CMD_STEPOUT_TU) {
philpem@48 283 ctx->last_step_dir = -1;
philpem@48 284 }
philpem@48 285
philpem@48 286 // Seek one step in the last direction used.
philpem@48 287 ctx->track += ctx->last_step_dir;
philpem@48 288 if (ctx->track < 0) ctx->track = 0;
philpem@48 289 if (ctx->track >= ctx->geom_tracks) {
philpem@48 290 // Seek past end of disc... that'll be a Seek Error then.
philpem@48 291 ctx->status = 0x10;
philpem@48 292 ctx->track = ctx->geom_tracks - 1;
philpem@48 293 }
philpem@48 294 is_type1 = true;
philpem@48 295 break;
philpem@48 296
philpem@48 297 default:
philpem@48 298 break;
philpem@48 299 }
philpem@48 300
philpem@48 301 if (is_type1) {
philpem@48 302 // Terminate any sector reads or writes
philpem@48 303 ctx->data_len = ctx->data_pos = 0;
philpem@48 304
philpem@48 305 // No DRQ bit for these commands.
philpem@48 306 ctx->cmd_has_drq = false;
philpem@48 307
philpem@48 308 // Type1 status byte...
philpem@48 309 ctx->status = 0;
philpem@48 310 // S7 = Not Ready. Command executed, therefore the drive was ready... :)
philpem@48 311 // S6 = Write Protect. TODO: add this
philpem@48 312 // S5 = Head Loaded. For certain emulation-related reasons, the heads are always loaded...
philpem@48 313 ctx->status |= 0x20;
philpem@48 314 // S4 = Seek Error. Not bloody likely if we got down here...!
philpem@48 315 // S3 = CRC Error. Not gonna happen on a disc image!
philpem@48 316 // S2 = Track 0
philpem@48 317 ctx->status |= (ctx->track == 0) ? 0x04 : 0x00;
philpem@48 318 // S1 = Index Pulse. TODO -- need periodics to emulate this
philpem@48 319 // S0 = Busy. We just exec'd the command, thus we're not busy.
philpem@48 320 // TODO: Set a timer for seeks, and ONLY clear BUSY when that timer expires. Need periodics for that.
philpem@48 321
philpem@48 322 // Set IRQ only if IRQL has been cleared (no pending IRQs)
philpem@53 323 ctx->irqe = ctx->irql ? ctx->irqe : true;
philpem@48 324 ctx->irql = true;
philpem@48 325 return;
philpem@48 326 }
philpem@48 327
philpem@48 328 // That's the Type 1 (seek) commands sorted. Now for the others.
philpem@48 329
philpem@53 330 // All these commands return the DRQ bit...
philpem@53 331 ctx->cmd_has_drq = true;
philpem@53 332
philpem@48 333 // If drive isn't ready, then set status B7 and exit
philpem@48 334 if (ctx->disc_image == NULL) {
philpem@48 335 ctx->status = 0x80;
philpem@48 336 return;
philpem@48 337 }
philpem@48 338
philpem@48 339 // If this is a Write command, check write protect status too
philpem@48 340 // TODO!
philpem@48 341 if (false) {
philpem@48 342 // Write protected disc...
philpem@48 343 if ((cmd == CMD_WRITE_SECTOR) || (cmd == CMD_WRITE_SECTOR_MULTI) || (cmd == CMD_FORMAT_TRACK)) {
philpem@48 344 // Set Write Protect bit and bail.
philpem@48 345 ctx->status = 0x40;
philpem@48 346
philpem@48 347 // Set IRQ only if IRQL has been cleared (no pending IRQs)
philpem@53 348 ctx->irqe = ctx->irql ? ctx->irqe : true;
philpem@48 349 ctx->irql = true;
philpem@48 350
philpem@48 351 return;
philpem@48 352 }
philpem@48 353 }
philpem@48 354
philpem@48 355 // Disc is ready to go. Parse the command word.
philpem@48 356 switch (cmd) {
philpem@48 357 case CMD_READ_ADDRESS:
philpem@48 358 // Read Address
philpem@54 359 ctx->head = (val & 0x02) ? 1 : 0;
philpem@48 360
philpem@48 361 // reset data pointers
philpem@48 362 ctx->data_pos = ctx->data_len = 0;
philpem@48 363
philpem@48 364 // load data buffer
philpem@48 365 ctx->data[ctx->data_len++] = ctx->track;
philpem@48 366 ctx->data[ctx->data_len++] = ctx->head;
philpem@48 367 ctx->data[ctx->data_len++] = ctx->sector;
philpem@48 368 switch (ctx->geom_secsz) {
philpem@48 369 case 128: ctx->data[ctx->data_len++] = 0; break;
philpem@48 370 case 256: ctx->data[ctx->data_len++] = 1; break;
philpem@48 371 case 512: ctx->data[ctx->data_len++] = 2; break;
philpem@48 372 case 1024: ctx->data[ctx->data_len++] = 3; break;
philpem@48 373 default: ctx->data[ctx->data_len++] = 0xFF; break; // TODO: deal with invalid values better
philpem@48 374 }
philpem@48 375 ctx->data[ctx->data_len++] = 0; // TODO: IDAM CRC!
philpem@48 376 ctx->data[ctx->data_len++] = 0;
philpem@48 377
philpem@53 378 ctx->status = 0;
philpem@48 379 // B6, B5 = 0
philpem@48 380 // B4 = Record Not Found. We're not going to see this... FIXME-not emulated
philpem@48 381 // B3 = CRC Error. Not possible.
philpem@48 382 // B2 = Lost Data. Caused if DRQ isn't serviced in time. FIXME-not emulated
philpem@48 383 // B1 = DRQ. Data request.
philpem@48 384 ctx->status |= (ctx->data_pos < ctx->data_len) ? 0x02 : 0x00;
philpem@48 385 break;
philpem@48 386
philpem@48 387 case CMD_READ_SECTOR:
philpem@48 388 case CMD_READ_SECTOR_MULTI:
philpem@54 389 ctx->head = (val & 0x02) ? 1 : 0;
philpem@71 390 LOG("WD279X: READ SECTOR cmd=%02X chs=%d:%d:%d", cmd, ctx->track, ctx->head, ctx->sector);
philpem@48 391 // Read Sector or Read Sector Multiple
philpem@57 392
philpem@57 393 // Check to see if the cyl, hd and sec are valid
philpem@57 394 if ((ctx->track > (ctx->geom_tracks-1)) || (ctx->head > (ctx->geom_heads-1)) || (ctx->sector > ctx->geom_spt) || (ctx->sector == 0)) {
philpem@71 395 LOG("*** WD2797 ALERT: CHS parameter limit exceeded! CHS=%d:%d:%d, maxCHS=%d:%d:%d",
philpem@57 396 ctx->track, ctx->head, ctx->sector,
philpem@57 397 ctx->geom_tracks-1, ctx->geom_heads-1, ctx->geom_spt);
philpem@57 398 // CHS parameters exceed limits
philpem@57 399 ctx->status = 0x10; // Record Not Found
philpem@57 400 break;
philpem@57 401 // Set IRQ only if IRQL has been cleared (no pending IRQs)
philpem@57 402 ctx->irqe = ctx->irql ? ctx->irqe : true;
philpem@57 403 ctx->irql = true;
philpem@57 404 }
philpem@57 405
philpem@48 406 // reset data pointers
philpem@48 407 ctx->data_pos = ctx->data_len = 0;
philpem@48 408
philpem@49 409 // Calculate number of sectors to read from disc
philpem@49 410 if (cmd == CMD_READ_SECTOR_MULTI)
philpem@49 411 temp = ctx->geom_spt;
philpem@49 412 else
philpem@49 413 temp = 1;
philpem@48 414
philpem@49 415 for (int i=0; i<temp; i++) {
philpem@49 416 // Calculate the LBA address of the required sector
philpem@57 417 // LBA = (C * nHeads * nSectors) + (H * nSectors) + S - 1
philpem@57 418 lba = (((ctx->track * ctx->geom_heads * ctx->geom_spt) + (ctx->head * ctx->geom_spt) + ctx->sector) + i) - 1;
philpem@57 419 // convert LBA to byte address
philpem@57 420 lba *= ctx->geom_secsz;
philpem@71 421 LOG("\tREAD lba = %lu", lba);
philpem@49 422
philpem@49 423 // Read the sector from the file
philpem@49 424 fseek(ctx->disc_image, lba, SEEK_SET);
philpem@71 425 // TODO: check fread return value! if < secsz, BAIL! (call it a crc error or secnotfound maybe? also log to stderr)
philpem@49 426 ctx->data_len += fread(&ctx->data[ctx->data_len], 1, ctx->geom_secsz, ctx->disc_image);
philpem@71 427 LOG("\tREAD len=%lu, pos=%lu, ssz=%d", ctx->data_len, ctx->data_pos, ctx->geom_secsz);
philpem@49 428 }
philpem@48 429
philpem@53 430 ctx->status = 0;
philpem@48 431 // B6 = 0
philpem@48 432 // B5 = Record Type -- 1 = deleted, 0 = normal. We can't emulate anything but normal data blocks.
philpem@57 433 // B4 = Record Not Found. Basically, the CHS parameters are bullcrap.
philpem@48 434 // B3 = CRC Error. Not possible.
philpem@48 435 // B2 = Lost Data. Caused if DRQ isn't serviced in time. FIXME-not emulated
philpem@48 436 // B1 = DRQ. Data request.
philpem@48 437 ctx->status |= (ctx->data_pos < ctx->data_len) ? 0x02 : 0x00;
philpem@48 438 break;
philpem@48 439
philpem@48 440 case CMD_READ_TRACK:
philpem@48 441 // Read Track
philpem@49 442 // TODO! implement this
philpem@54 443 ctx->head = (val & 0x02) ? 1 : 0;
philpem@53 444 ctx->status = 0;
philpem@48 445 // B6, B5, B4, B3 = 0
philpem@48 446 // B2 = Lost Data. Caused if DRQ isn't serviced in time. FIXME-not emulated
philpem@48 447 // B1 = DRQ. Data request.
philpem@48 448 ctx->status |= (ctx->data_pos < ctx->data_len) ? 0x02 : 0x00;
philpem@48 449 break;
philpem@48 450
philpem@48 451 case CMD_WRITE_SECTOR:
philpem@48 452 case CMD_WRITE_SECTOR_MULTI:
philpem@48 453 // Write Sector or Write Sector Multiple
philpem@48 454
philpem@54 455 ctx->head = (val & 0x02) ? 1 : 0;
philpem@48 456 // reset data pointers
philpem@48 457 ctx->data_pos = ctx->data_len = 0;
philpem@48 458
philpem@48 459 // TODO: set "write pending" flag, and write LBA, and go from there.
philpem@48 460
philpem@53 461 ctx->status = 0;
philpem@48 462 // B6 = Write Protect. FIXME -- emulate this!
philpem@48 463 // B5 = 0
philpem@48 464 // B4 = Record Not Found. We're not going to see this... FIXME-not emulated
philpem@48 465 // B3 = CRC Error. Not possible.
philpem@48 466 // B2 = Lost Data. Caused if DRQ isn't serviced in time. FIXME-not emulated
philpem@48 467 // B1 = DRQ. Data request.
philpem@48 468 ctx->status |= (ctx->data_pos < ctx->data_len) ? 0x02 : 0x00;
philpem@48 469 break;
philpem@48 470
philpem@48 471 case CMD_FORMAT_TRACK:
philpem@48 472 // Write Track (aka Format Track)
philpem@54 473 ctx->head = (val & 0x02) ? 1 : 0;
philpem@53 474 ctx->status = 0;
philpem@48 475 // B6 = Write Protect. FIXME -- emulate this!
philpem@48 476 // B5, B4, B3 = 0
philpem@48 477 // B2 = Lost Data. Caused if DRQ isn't serviced in time. FIXME-not emulated
philpem@48 478 // B1 = DRQ. Data request.
philpem@48 479 ctx->status |= (ctx->data_pos < ctx->data_len) ? 0x02 : 0x00;
philpem@48 480 break;
philpem@48 481
philpem@48 482 case CMD_FORCE_INTERRUPT:
philpem@48 483 // Force Interrupt...
philpem@49 484 // Terminates current operation and sends an interrupt
philpem@49 485 // TODO!
philpem@53 486 ctx->status = 0;
philpem@49 487 ctx->data_pos = ctx->data_len = 0;
philpem@49 488 // Set IRQ only if IRQL has been cleared (no pending IRQs)
philpem@53 489 ctx->irqe = ctx->irql ? ctx->irqe : true;
philpem@49 490 ctx->irql = true;
philpem@48 491 break;
philpem@48 492 }
philpem@48 493 break;
philpem@48 494
philpem@49 495 case WD2797_REG_TRACK: // Track register
philpem@48 496 ctx->track = val;
philpem@48 497 break;
philpem@48 498
philpem@49 499 case WD2797_REG_SECTOR: // Sector register
philpem@48 500 ctx->sector = val;
philpem@48 501 break;
philpem@48 502
philpem@49 503 case WD2797_REG_DATA: // Data register
philpem@48 504 // Save the value written into the data register
philpem@48 505 ctx->data_reg = val;
philpem@48 506
philpem@48 507 // If we're processing a write command, and there's space in the
philpem@48 508 // buffer, allow the write.
philpem@48 509 if (ctx->data_pos < ctx->data_len) {
philpem@53 510 // set IRQ if this is the last data byte
philpem@53 511 if (ctx->data_pos == (ctx->data_len-1)) {
philpem@53 512 // Set IRQ only if IRQL has been cleared (no pending IRQs)
philpem@53 513 ctx->irqe = ctx->irql ? ctx->irqe : true;
philpem@53 514 ctx->irql = true;
philpem@53 515 }
philpem@53 516
philpem@48 517 // store data byte and increment pointer
philpem@48 518 ctx->data[ctx->data_pos++] = val;
philpem@48 519 }
philpem@48 520 break;
philpem@48 521 }
philpem@48 522 }
philpem@48 523