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/*

 * load.c -- load S-records from serial line

 */

#include "common.h"

#include "stdarg.h"

#include "romlib.h"

#include "load.h"

#include "serial.h"

#include "cpu.h"

#include "mmu.h"

#define NUM_TRIES       10

#define WAIT_DELAY      350000

#define SYN             ((unsigned char) 's')

#define ACK             ((unsigned char) 'a')

#define LINE_SIZE       520

static Byte line[LINE_SIZE];

static Word getByte(int index) {

  Word hi, lo;

  hi = line[index + 0];

  if (hi >= '0' && hi <= '9') {

    hi -= '0';

  } else

  if (hi >= 'A' && hi <= 'F') {

    hi -= 'A' - 10;

  } else

  if (hi >= 'a' && hi <= 'f') {

    hi -= 'a' - 10;

  } else {

    return -1;

  }

  lo = line[index + 1];

  if (lo >= '0' && lo <= '9') {

    lo -= '0';

  } else

  if (lo >= 'A' && lo <= 'F') {

    lo -= 'A' - 10;

  } else

  if (lo >= 'a' && lo <= 'f') {

    lo -= 'a' - 10;

  } else {

    return -1;

  }

  return (hi << 4) | lo;

}

static void serialOut(int serno, Word c) {

  if (serno == 0) {

    ser0out(c);

  } else {

    ser1out(c);

  }

}

static int serialChk(int serno) {

  if (serno == 0) {

    return ser0inchk();

  } else {

    return ser1inchk();

  }

}

static Word serialIn(int serno) {

  if (serno == 0) {

    return ser0in();

  } else {

    return ser1in();

  }

}

void load(int serno, Bool start) {

  int i, j;

  Bool run;

  int type;

  int count;

  Word chksum;

  Word addr;

  Byte b;

  printf("Trying to connect to load server...\n");

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

    serialOut(serno, SYN);

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

      if (serialChk(serno) != 0) {

        break;

      }

    }

    if (j < WAIT_DELAY) {

      break;

    }

    printf("Request timed out...\n");

  }

  if (i == NUM_TRIES ||

      serialIn(serno) != ACK) {

    printf("Unable to establish connection to load server.\n");

    return;

  }

  serialOut(serno, ACK);

  printf("Connected to load server.\n");

  run = true;

  while (run) {

    serialOut(serno, 'r');

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

      line[i] = serialIn(serno);

      if (line[i] == '\n') {

        break;

      }

    }

    if (i == LINE_SIZE) {

      printf("Error: too many characters in S-record!\n");

      break;

    }

    line[i] = '\0';

    printf("%s\n", line);

    if (line[0] != 'S') {

      printf("Error: malformed S-record!\n");

      break;

    }

    type = line[1];

    count = getByte(2);

    if (i != 2 * count + 4) {

      printf("Error: inconsistent byte count in S-record!\n");

      break;

    }

    chksum = 0;

    for (j = 2; j < i; j += 2) {

      chksum += getByte(j);

    }

    if ((chksum & 0xFF) != 0xFF) {

      printf("Error: wrong checksum in S-record!\n");

      break;

    }

    switch (type) {

      case '0':

        /* S0 record: header (skip) */

        break;

      case '1':

        /* S1 record: 2 byte load address + data (load data) */

        addr = (getByte( 4) <<  8) |

               (getByte( 6) <<  0);

        addr |= 0xC0000000;

        for (j = 0; j < count - 3; j++) {

          b = getByte(2 * j + 8);

          mmuWriteByte(addr + j, b);

        }

        break;

      case '2':

        /* S2 record: 3 byte load address + data (load data) */

        addr = (getByte( 4) << 16) |

               (getByte( 6) <<  8) |

               (getByte( 8) <<  0);

        addr |= 0xC0000000;

        for (j = 0; j < count - 4; j++) {

          b = getByte(2 * j + 10);

          mmuWriteByte(addr + j, b);

        }

        break;

      case '3':

        /* S3 record: 4 byte load address + data (load data) */

        addr = (getByte( 4) << 24) |

               (getByte( 6) << 16) |

               (getByte( 8) <<  8) |

               (getByte(10) <<  0);

        addr |= 0xC0000000;

        for (j = 0; j < count - 5; j++) {

          b = getByte(2 * j + 12);

          mmuWriteByte(addr + j, b);

        }

        break;

      case '5':

        /* S5 record: record count (skip) */

        break;

      case '7':

        /* S7 record: 4 byte start address (set PC, stop loading) */

        addr = (getByte( 4) << 24) |

               (getByte( 6) << 16) |

               (getByte( 8) <<  8) |

               (getByte(10) <<  0);

        addr |= 0xC0000000;

        cpuSetPC(addr);

        run = false;

        break;

      case '8':

        /* S8 record: 3 byte start address (set PC, stop loading) */

        addr = (getByte( 4) << 16) |

               (getByte( 6) <<  8) |

               (getByte( 8) <<  0);

        addr |= 0xC0000000;

        cpuSetPC(addr);

        run = false;

        break;

      case '9':

        /* S9 record: 2 byte start address (set PC, stop loading) */

        addr = (getByte( 4) <<  8) |

               (getByte( 6) <<  0);

        addr |= 0xC0000000;

        cpuSetPC(addr);

        run = false;

        break;

      default:

        /* unknown type of S-record */

        printf("Error: unknown type of S-record!\n");

        run = false;

        break;

    }

  }

  serialOut(serno, 'q');

  printf("Connection to load server closed.\n");

  if (start) {

    cpuRun();

  }

}