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");
}