linux/arch/x86/lib/string_32.c
Andi Kleen 61d08a9ea3 i386: Remove strrchr assembler implementation
The constraints in the inline assembler implementation of i386
strrchr() were incorrect and break the build with recent gcc 4.3.
Since there are only very few callers of strrchr() and none of them
are performance relevant just remove the assembler implementation
and use the C fallback instead.

[ tglx: arch/x86 adaptation ]

Cc: rguenther@suse.de
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2007-10-17 20:16:23 +02:00

238 lines
4.6 KiB
C

/*
* Most of the string-functions are rather heavily hand-optimized,
* see especially strsep,strstr,str[c]spn. They should work, but are not
* very easy to understand. Everything is done entirely within the register
* set, making the functions fast and clean. String instructions have been
* used through-out, making for "slightly" unclear code :-)
*
* AK: On P4 and K7 using non string instruction implementations might be faster
* for large memory blocks. But most of them are unlikely to be used on large
* strings.
*/
#include <linux/string.h>
#include <linux/module.h>
#ifdef __HAVE_ARCH_STRCPY
char *strcpy(char * dest,const char *src)
{
int d0, d1, d2;
asm volatile( "1:\tlodsb\n\t"
"stosb\n\t"
"testb %%al,%%al\n\t"
"jne 1b"
: "=&S" (d0), "=&D" (d1), "=&a" (d2)
:"0" (src),"1" (dest) : "memory");
return dest;
}
EXPORT_SYMBOL(strcpy);
#endif
#ifdef __HAVE_ARCH_STRNCPY
char *strncpy(char * dest,const char *src,size_t count)
{
int d0, d1, d2, d3;
asm volatile( "1:\tdecl %2\n\t"
"js 2f\n\t"
"lodsb\n\t"
"stosb\n\t"
"testb %%al,%%al\n\t"
"jne 1b\n\t"
"rep\n\t"
"stosb\n"
"2:"
: "=&S" (d0), "=&D" (d1), "=&c" (d2), "=&a" (d3)
:"0" (src),"1" (dest),"2" (count) : "memory");
return dest;
}
EXPORT_SYMBOL(strncpy);
#endif
#ifdef __HAVE_ARCH_STRCAT
char *strcat(char * dest,const char * src)
{
int d0, d1, d2, d3;
asm volatile( "repne\n\t"
"scasb\n\t"
"decl %1\n"
"1:\tlodsb\n\t"
"stosb\n\t"
"testb %%al,%%al\n\t"
"jne 1b"
: "=&S" (d0), "=&D" (d1), "=&a" (d2), "=&c" (d3)
: "0" (src), "1" (dest), "2" (0), "3" (0xffffffffu): "memory");
return dest;
}
EXPORT_SYMBOL(strcat);
#endif
#ifdef __HAVE_ARCH_STRNCAT
char *strncat(char * dest,const char * src,size_t count)
{
int d0, d1, d2, d3;
asm volatile( "repne\n\t"
"scasb\n\t"
"decl %1\n\t"
"movl %8,%3\n"
"1:\tdecl %3\n\t"
"js 2f\n\t"
"lodsb\n\t"
"stosb\n\t"
"testb %%al,%%al\n\t"
"jne 1b\n"
"2:\txorl %2,%2\n\t"
"stosb"
: "=&S" (d0), "=&D" (d1), "=&a" (d2), "=&c" (d3)
: "0" (src),"1" (dest),"2" (0),"3" (0xffffffffu), "g" (count)
: "memory");
return dest;
}
EXPORT_SYMBOL(strncat);
#endif
#ifdef __HAVE_ARCH_STRCMP
int strcmp(const char * cs,const char * ct)
{
int d0, d1;
int res;
asm volatile( "1:\tlodsb\n\t"
"scasb\n\t"
"jne 2f\n\t"
"testb %%al,%%al\n\t"
"jne 1b\n\t"
"xorl %%eax,%%eax\n\t"
"jmp 3f\n"
"2:\tsbbl %%eax,%%eax\n\t"
"orb $1,%%al\n"
"3:"
:"=a" (res), "=&S" (d0), "=&D" (d1)
:"1" (cs),"2" (ct)
:"memory");
return res;
}
EXPORT_SYMBOL(strcmp);
#endif
#ifdef __HAVE_ARCH_STRNCMP
int strncmp(const char * cs,const char * ct,size_t count)
{
int res;
int d0, d1, d2;
asm volatile( "1:\tdecl %3\n\t"
"js 2f\n\t"
"lodsb\n\t"
"scasb\n\t"
"jne 3f\n\t"
"testb %%al,%%al\n\t"
"jne 1b\n"
"2:\txorl %%eax,%%eax\n\t"
"jmp 4f\n"
"3:\tsbbl %%eax,%%eax\n\t"
"orb $1,%%al\n"
"4:"
:"=a" (res), "=&S" (d0), "=&D" (d1), "=&c" (d2)
:"1" (cs),"2" (ct),"3" (count)
:"memory");
return res;
}
EXPORT_SYMBOL(strncmp);
#endif
#ifdef __HAVE_ARCH_STRCHR
char *strchr(const char * s, int c)
{
int d0;
char * res;
asm volatile( "movb %%al,%%ah\n"
"1:\tlodsb\n\t"
"cmpb %%ah,%%al\n\t"
"je 2f\n\t"
"testb %%al,%%al\n\t"
"jne 1b\n\t"
"movl $1,%1\n"
"2:\tmovl %1,%0\n\t"
"decl %0"
:"=a" (res), "=&S" (d0)
:"1" (s),"0" (c)
:"memory");
return res;
}
EXPORT_SYMBOL(strchr);
#endif
#ifdef __HAVE_ARCH_STRLEN
size_t strlen(const char * s)
{
int d0;
int res;
asm volatile( "repne\n\t"
"scasb\n\t"
"notl %0\n\t"
"decl %0"
:"=c" (res), "=&D" (d0)
:"1" (s),"a" (0), "0" (0xffffffffu)
:"memory");
return res;
}
EXPORT_SYMBOL(strlen);
#endif
#ifdef __HAVE_ARCH_MEMCHR
void *memchr(const void *cs,int c,size_t count)
{
int d0;
void *res;
if (!count)
return NULL;
asm volatile( "repne\n\t"
"scasb\n\t"
"je 1f\n\t"
"movl $1,%0\n"
"1:\tdecl %0"
:"=D" (res), "=&c" (d0)
:"a" (c),"0" (cs),"1" (count)
:"memory");
return res;
}
EXPORT_SYMBOL(memchr);
#endif
#ifdef __HAVE_ARCH_MEMSCAN
void *memscan(void * addr, int c, size_t size)
{
if (!size)
return addr;
asm volatile("repnz; scasb\n\t"
"jnz 1f\n\t"
"dec %%edi\n"
"1:"
: "=D" (addr), "=c" (size)
: "0" (addr), "1" (size), "a" (c)
: "memory");
return addr;
}
EXPORT_SYMBOL(memscan);
#endif
#ifdef __HAVE_ARCH_STRNLEN
size_t strnlen(const char *s, size_t count)
{
int d0;
int res;
asm volatile( "movl %2,%0\n\t"
"jmp 2f\n"
"1:\tcmpb $0,(%0)\n\t"
"je 3f\n\t"
"incl %0\n"
"2:\tdecl %1\n\t"
"cmpl $-1,%1\n\t"
"jne 1b\n"
"3:\tsubl %2,%0"
:"=a" (res), "=&d" (d0)
:"c" (s),"1" (count)
:"memory");
return res;
}
EXPORT_SYMBOL(strnlen);
#endif