string.c

/* SPDX-License-Identifier: MIT */

#include <string.h>
#include <stdint.h>

void *memset(void *dest, int c, size_t count)
{
    uint8_t *dst = (uint8_t *)dest;
    size_t   nabytes = (-(size_t)dest) & (sizeof(size_t) - 1);
    size_t   val = c & 0xff;

    /* if we have to set both aligned and non aligned bytes */
    if (count > nabytes) {
        count -= nabytes;

        val |= val << 8;
        val |= val << 16;
        val |= val << 32;

        /* set the non-aligned bytes memory byte-wise */
        for (; nabytes > 0; nabytes--) {
            *dst++ = c;
        }

        /* set the aligned bytes using dword */
        size_t abytes = count / sizeof(size_t);
        for (; abytes > 0; abytes--) {
            *((size_t *)dst) = val;
            dst += sizeof(size_t);
        }
    }

    for (; count > 0; count--) {
        *dst++ = val;
    }

    return dest;
}

void *memchr(void const *ptr, int value, size_t count)
{
    return NULL;
}

int memcmp(void const *a, void const *b, size_t count)
{
    return 0;
}

void *memcpy(void *dest, void const *src, size_t count)
{
    uint8_t *dst = (uint8_t *)dest;
    uint8_t *s = (uint8_t *)src;

    for (; count > 0; count--) {
        *(dst++) = *(s++);
    }

    return dest;
}

void *memmove(void *dest, void const *src, size_t count)
{
    return NULL;
}