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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)
{
#ifdef userspace
// Inspired by Jeko at osdev
u8 *dest_byte = dest;
const u8 *src_byte = src;
for (u32 i = 0; i < n / 16; i++) {
__asm__ volatile("movups (%0), %%xmm0\n"
"movntdq %%xmm0, (%1)\n" ::"r"(src_byte),
"r"(dest_byte)
: "memory");
src_byte += 16;
dest_byte += 16;
}
if (n & 7) {
n = n & 7;
int d0, d1, d2;
__asm__ volatile("rep ; movsl\n\t"
"testb $2,%b4\n\t"
"je 1f\n\t"
"movsw\n"
"1:\ttestb $1,%b4\n\t"
"je 2f\n\t"
"movsb\n"
"2:"
: "=&c"(d0), "=&D"(d1), "=&S"(d2)
: "0"(n / 4), "q"(n), "1"((long)dest_byte), "2"((long)src_byte)
: "memory");
}
return dest_byte;
#else
// 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;
// TODO: What's faster?
__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_dwords; i++) { */
/* dest32[i] = src32[i]; */
/* } */
for (u32 i = 0; i < num_bytes; i++) {
dest8[i] = src8[i];
}
return dest;
#endif
}
void *memset(void *dest, u32 val, u32 n)
{
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);
// TODO: What's faster?
__asm__ volatile("rep stosl\n"
: "=D"(dest32), "=c"(num_dwords)
: "D"(dest32), "c"(num_dwords), "a"(val32)
: "memory");
/* for (u32 i = 0; i < num_dwords; i++) { */
/* dest32[i] = val32; */
/* } */
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;
}
int 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;
}
int mememp(const u8 *buf, u32 n)
{
return buf[0] == 0 && !memcmp(buf, buf + 1, n - 1);
}
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