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/*

 * main.c -- dump the master boot record of a disk

 */

#include "types.h"

#include "stdarg.h"

#include "iolib.h"

#include "start.h"

#include "idedsk.h"

/**************************************************************/

void error(char *fmt, ...) {

  va_list ap;

  va_start(ap, fmt);

  printf("Error: ");

  vprintf(fmt, ap);

  printf(", halting...\n");

  va_end(ap);

  while (1) ;

}

/**************************************************************/

static char *exceptionCause[32] = {

  /* 00 */  "terminal 0 transmitter interrupt",

  /* 01 */  "terminal 0 receiver interrupt",

  /* 02 */  "terminal 1 transmitter interrupt",

  /* 03 */  "terminal 1 receiver interrupt",

  /* 04 */  "keyboard interrupt",

  /* 05 */  "unknown interrupt",

  /* 06 */  "unknown interrupt",

  /* 07 */  "unknown interrupt",

  /* 08 */  "disk interrupt",

  /* 09 */  "unknown interrupt",

  /* 10 */  "unknown interrupt",

  /* 11 */  "unknown interrupt",

  /* 12 */  "unknown interrupt",

  /* 13 */  "unknown interrupt",

  /* 14 */  "timer 0 interrupt",

  /* 15 */  "timer 1 interrupt",

  /* 16 */  "bus timeout exception",

  /* 17 */  "illegal instruction exception",

  /* 18 */  "privileged instruction exception",

  /* 19 */  "divide instruction exception",

  /* 20 */  "trap instruction exception",

  /* 21 */  "TLB miss exception",

  /* 22 */  "TLB write exception",

  /* 23 */  "TLB invalid exception",

  /* 24 */  "illegal address exception",

  /* 25 */  "privileged address exception",

  /* 26 */  "unknown exception",

  /* 27 */  "unknown exception",

  /* 28 */  "unknown exception",

  /* 29 */  "unknown exception",

  /* 30 */  "unknown exception",

  /* 31 */  "unknown exception"

};

int defaultISR(int irq) {

  printf("\n%s\n", exceptionCause[irq]);

  return 0;  /* do not skip any instruction */

}

void initInterrupts(void) {

  int i;

  for (i = 0; i < 32; i++) {

    setISR(i, defaultISR);

  }

}

/**************************************************************/

Bool checkDiskReady(void) {

  int tries;

  int i;

  for (tries = 0; tries < 10; tries++) {

    for (i = 0; i < 500000; i++) {

      if ((*DISK_CTRL & DISK_CTRL_READY) != 0) {

        return TRUE;

      }

    }

    printf(".");

  }

  return FALSE;

}

unsigned long getDiskSize(void) {

  return *DISK_CAP;

}

Bool readDisk(unsigned long sector,

              unsigned int count,

              unsigned int *addr) {

  unsigned int n;

  unsigned int *p;

  unsigned int i;

  while (count != 0) {

    n = count > 8 ? 8 : count;

    *DISK_SCT = sector;

    *DISK_CNT = n;

    *DISK_CTRL = DISK_CTRL_STRT;

    while ((*DISK_CTRL & DISK_CTRL_DONE) == 0) ;

    if (*DISK_CTRL & DISK_CTRL_ERR) {

      return FALSE;

    }

    p = DISK_BUFFER;

    for (i = 0; i < n * SECTOR_SIZE / sizeof(unsigned int); i++) {

      *addr++ = *p++;

    }

    sector += n;

    count -= n;

  }

  return TRUE;

}

/**************************************************************/

void main(void) {

  unsigned long numSectors;

  unsigned int buffer[SECTOR_SIZE / sizeof(unsigned int)];

  int i, j;

  unsigned char *p, *q;

  unsigned char c;

  /* init interrupts */

  initInterrupts();

  /* check disk ready */

  if (!checkDiskReady()) {

    error("disk not ready");

  }

  /* determine disk size */

  numSectors = getDiskSize();

  printf("Disk has %lu (0x%lX) sectors.\n",

         numSectors, numSectors);

  if (numSectors < 32) {

    error("disk is too small");

  }

  /* read master boot record */

  if (!readDisk(0, 1, buffer)) {

    error("cannot read master boot record from disk");

  }

  /* dump master boot record */

  p = (unsigned char *) buffer;

  for (i = 0; i < 32; i++) {

    printf("%08X:  ", i * 16);

    q = p;

    for (j = 0; j < 16; j++) {

      c = *q++;

      printf("%02X ", c);

    }

    printf("  ");

    q = p;

    for (j = 0; j < 16; j++) {

      c = *q++;

      if (c >= 32 && c <= 126) {

        printf("%c", c);

      } else {

        printf(".");

      }

    }

    printf("\n");

    p = q;

  }

  /* done */

  printf("Halting...\n");

}