Subversion Repositories openrisc_2011-10-31

#include "lib-utils.h"
 
/* Simple C functions */
 
/* memcpy */
 
void* memcpy( void* s1, void* s2, size_t n)
{
  char* r1 = (char *) s1;
  const char* r2 =  (const char*) s2;
#ifdef __BCC__
  while (n--) {
    *r1++ = *r2++;
  }
#else
  while (n) {
    *r1++ = *r2++;
    --n;
  }
#endif
  return s1;
}
 
/* strlen */
size_t strlen(const char*s)
{
  const char* p;
  for (p=s; *p; p++);
  return p - s;
}
 
/* memchr */
void *memchr(const void *s, int c, size_t n)
{
         const unsigned char *r = (const unsigned char *) s;
#ifdef __BCC__
        /* bcc can optimize the counter if it thinks it is a pointer... */
        const char *np = (const char *) n;
#else
# define np n
#endif
 
        while (np) {
                if (*r == ((unsigned char)c)) {
                        return (void *) r;     /* silence the warning */
                }
                ++r;
                --np;
        }
 
        return NULL;
}
 
/* --------------------------------------------------------------------------*/
/*!Pseudo-random number generator
 
   This should return pseudo-random numbers, based on a Galois LFSR
 
   @return The next pseudo-random number                                     */
/* --------------------------------------------------------------------------*/
unsigned long int
rand ()
{
  static unsigned long int lfsr = RAND_LFSR_SEED;
  static int period = 0;
  /* taps: 32 31 29 1; characteristic polynomial: x^32 + x^31 + x^29 + x + 1 */
  lfsr = (lfsr >> 1) ^ (unsigned long int)((0 - (lfsr & 1u)) & 0xd0000001u); 
  ++period;
  return lfsr;
}