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/*
* Copyright (c) 2014 Richard Braun.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <kern/param.h>
#include <kern/stddef.h>
#include <kern/string.h>
#ifdef ARCH_STRING_MEMCPY
void *
memcpy(void *dest, const void *src, size_t n)
{
void *orig_dest;
orig_dest = dest;
asm volatile("rep movsb" : "+D" (dest), "+S" (src), "+c" (n));
return orig_dest;
}
#endif /* ARCH_STRING_MEMCPY */
#ifdef ARCH_STRING_MEMMOVE
void *
memmove(void *dest, const void *src, size_t n)
{
void *orig_dest;
orig_dest = dest;
if (dest <= src)
asm volatile("rep movsb" : "+D" (dest), "+S" (src), "+c" (n));
else {
dest += n - 1;
src += n - 1;
asm volatile("std; rep movsb; cld" : "+D" (dest), "+S" (src), "+c" (n));
}
return orig_dest;
}
#endif /* ARCH_STRING_MEMMOVE */
#ifdef ARCH_STRING_MEMSET
void *
memset(void *s, int c, size_t n)
{
void *orig_s;
orig_s = s;
asm volatile("rep stosb" : "+D" (s), "+c" (n) : "a" (c));
return orig_s;
}
#endif /* ARCH_STRING_MEMSET */
#ifdef ARCH_STRING_MEMCMP
int
memcmp(const void *s1, const void *s2, size_t n)
{
unsigned char c1, c2;
if (n == 0)
return 0;
asm volatile("repe cmpsb\n" : "+D" (s1), "+S" (s2), "+c" (n));
c1 = *(((const unsigned char *)s1) - 1);
c2 = *(((const unsigned char *)s2) - 1);
return (int)c1 - (int)c2;
}
#endif /* ARCH_STRING_MEMCMP */
#ifdef ARCH_STRING_STRLEN
size_t
strlen(const char *s)
{
size_t n;
n = (size_t)-1;
asm volatile("repne scasb" : "+D" (s), "+c" (n) : "a" (0));
return ~n - 1;
}
#endif /* ARCH_STRING_STRLEN */
#ifdef ARCH_STRING_STRCPY
char *
strcpy(char *dest, const char *src)
{
char *orig_dest;
orig_dest = dest;
asm volatile("1:\n"
"lodsb\n"
"stosb\n"
"testb %%al, %%al\n"
"jnz 1b\n"
: "+D" (dest), "+S" (src) : : "al");
return orig_dest;
}
#endif /* ARCH_STRING_STRCPY */
#ifdef ARCH_STRING_STRCMP
int
strcmp(const char *s1, const char *s2)
{
unsigned char c1, c2;
asm volatile("1:\n"
"lodsb\n"
"scasb\n"
"jne 1f\n"
"testb %%al, %%al\n"
"jnz 1b\n"
"1:\n"
: "+D" (s1), "+S" (s2) : : "al");
c1 = *(((const unsigned char *)s1) - 1);
c2 = *(((const unsigned char *)s2) - 1);
return (int)c1 - (int)c2;
}
#endif /* ARCH_STRING_STRCMP */
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