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// MIT License, Copyright (c) 2020 Marvin Borner
#include <assert.h>
#include <def.h>
#include <mem.h>
#include <sys.h>
void *memcpy(void *dest, const void *src, u32 n)
{
// Inspired by jgraef at osdev
u32 num_dwords = n / 4;
u32 num_bytes = n % 4;
u32 *dest32 = (u32 *)dest;
const u32 *src32 = (const u32 *)src;
u8 *dest8 = ((u8 *)dest) + num_dwords * 4;
const u8 *src8 = ((const u8 *)src) + num_dwords * 4;
__asm__ volatile("rep movsl\n"
: "=S"(src32), "=D"(dest32), "=c"(num_dwords)
: "S"(src32), "D"(dest32), "c"(num_dwords)
: "memory");
for (u32 i = 0; i < num_bytes; i++)
dest8[i] = src8[i];
return dest;
}
void *memset(void *dest, u32 val, u32 n)
{
// Inspired by jgraef at osdev
u32 uval = val;
u32 num_dwords = n / 4;
u32 num_bytes = n % 4;
u32 *dest32 = (u32 *)dest;
u8 *dest8 = ((u8 *)dest) + num_dwords * 4;
u8 val8 = (u8)val;
u32 val32 = uval | (uval << 8) | (uval << 16) | (uval << 24);
__asm__ volatile("rep stosl\n"
: "=D"(dest32), "=c"(num_dwords)
: "D"(dest32), "c"(num_dwords), "a"(val32)
: "memory");
for (u32 i = 0; i < num_bytes; i++)
dest8[i] = val8;
return dest;
}
void *memchr(void *src, char c, u32 n)
{
u8 *s = (u8 *)src;
while (n-- > 0) {
if (*s == c)
return s;
s++;
}
return NULL;
}
s32 memcmp(const void *s1, const void *s2, u32 n)
{
const u8 *a = (const u8 *)s1;
const u8 *b = (const u8 *)s2;
for (u32 i = 0; i < n; i++) {
if (a[i] < b[i])
return -1;
else if (b[i] < a[i])
return 1;
}
return 0;
}
u8 mememp(const u8 *buf, u32 n)
{
return buf[0] == 0 && !memcmp(buf, buf + 1, n - 1);
}
#ifdef KERNEL
#include <drivers/cpu.h>
void *memcpy_user(void *dest, const void *src, u32 n)
{
stac();
void *ret = memcpy(dest, src, n);
clac();
return ret;
}
void *memset_user(void *dest, u32 val, u32 n)
{
stac();
void *ret = memset(dest, val, n);
clac();
return ret;
}
void *memchr_user(void *src, char c, u32 n)
{
stac();
void *ret = memchr(src, c, n);
clac();
return ret;
}
s32 memcmp_user(const void *s1, const void *s2, u32 n)
{
stac();
s32 ret = memcmp(s1, s2, n);
clac();
return ret;
}
#endif
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