userland/libc/string/memcpy.c


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#include <string.h>

void *memcpy(void *dest, const void *src, uint32_t n) {
  unsigned char *d = dest;
  const unsigned char *s = src;

  for (; n >= 8; n -= 8, d += 8, s += 8) {
    *(uint64_t *)d = *(uint64_t *)s;
  }

  for (; n >= 4; n -= 4, d += 4, s += 4) {
    *(uint32_t *)d = *(uint32_t *)s;
  }

  for (; n >= 2; n -= 2, d += 2, s += 2) {
    *(uint16_t *)d = *(uint16_t *)s;
  }
  for (; n; n--) {
    *d++ = *s++;
  }
  return dest;
}