Subversion Repositories eco32

/*

 * main.c -- start the ball rolling

 */

#include "stdarg.h"

#include "start.h"

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

void putchar(char c) {

  unsigned int *base;

  if (c == '\n') {

    putchar('\r');

  }

  base = (unsigned int *) 0xF0300000;

  while ((*(base + 2) & 1) == 0) ;

  *(base + 3) = c;

}

void puts(char *s) {

  char c;

  while ((c = *s++) != '\0') {

    putchar(c);

  }

}

void printn(int n) {

  int a;

  if (n < 0) {

    putchar('-');

    n = -n;

  }

  a = n / 10;

  if (a != 0) {

    printn(a);

  }

  putchar(n % 10 + '0');

}

void printu(unsigned int n, unsigned int b) {

  unsigned int a;

  a = n / b;

  if (a != 0) {

    printu(a, b);

  }

  putchar("0123456789ABCDEF"[n % b]);

}

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

  va_list ap;

  char c;

  int n;

  unsigned int u;

  char *s;

  va_start(ap, fmt);

  while (1) {

    while ((c = *fmt++) != '%') {

      if (c == '\0') {

        va_end(ap);

        return;

      }

      putchar(c);

    }

    c = *fmt++;

    if (c == 'd') {

      n = va_arg(ap, int);

      printn(n);

    } else

    if (c == 'u' || c == 'o' || c == 'x') {

      u = va_arg(ap, int);

      printu(u, c == 'o' ? 8 : (c == 'x' ? 16 : 10));

    } else

    if (c == 's') {

      s = va_arg(ap, char *);

      puts(s);

    } else {

      putchar(c);

    }

  }

}

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

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);

  }

}

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

static int busTimeoutSeen;

int busTimeoutISR(int irq) {

  busTimeoutSeen = 1;

  return 1;  /* skip offending instruction */

}

int memsize(void) {

  unsigned char *ptr;

  unsigned char b;

  ISR oldService;

  busTimeoutSeen = 0;

  oldService = getISR(16);

  setISR(16, busTimeoutISR);

  ptr = (unsigned char *) 0xC0000000;

  while (1) {

    b = *ptr;

    if (busTimeoutSeen) {

      break;

    }

    ptr += (1 << 12);

  }

  setISR(16, oldService);

  return (ptr - (unsigned char *) 0xC0000000) >> 12;

}

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

void main(void) {

  int numberPages;

  initInterrupts();

  printf("\n");

  printf("Probing memory...\n");

  numberPages = memsize();

  printf("Memory size = %d pages * 4 Kbytes\n", numberPages);

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

}