/* sieve of Eratosthenes to demonstrate TinyMips in Hades */

#include <stdio.h>

static int limit;    // sieve size
static int *sieve;   // pointer to the sieve array


int main( int argc, char** argv ) {

  int i;
  int j;

  limit = 256; // 16384; 
  sieve = (void*) 0x00000200;

  // initialization loop
  for( i=0; i < limit; i++ ) {
    *(sieve+i) = 0xCCCCCCCC;
  }

  // first loop iteration marks all multiples of 2
  for( i=4; i < limit; i = i+2 ) {
    *(sieve+i) = 2;
  }

  // next nested loop marks all multiples of 3,5,7,...
  for( i=3; i < limit; i = i+2 ) {
    *(sieve-1) = i;

    for( j=(i+i); j < limit; j = j+i ) {
      *(sieve+j) = i;
    }
  }

  // endless loop that writes the detected primes to *(sieve-2)
  for( ;; ) {
    for( i=0; i < limit; i++ ) {
      if (*(sieve+i) == 0xCCCCCCCC) {
        *(sieve-2) = i;
      }
    }
  }
}