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Diffstat (limited to 'arch/i386/lib/string.c')
| -rw-r--r-- | arch/i386/lib/string.c | 257 |
1 files changed, 257 insertions, 0 deletions
diff --git a/arch/i386/lib/string.c b/arch/i386/lib/string.c new file mode 100644 index 000000000000..2c773fefa3dd --- /dev/null +++ b/arch/i386/lib/string.c @@ -0,0 +1,257 @@ +/* + * 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_STRRCHR +char *strrchr(const char * s, int c) +{ + int d0, d1; + char * res; + asm volatile( "movb %%al,%%ah\n" + "1:\tlodsb\n\t" + "cmpb %%ah,%%al\n\t" + "jne 2f\n\t" + "leal -1(%%esi),%0\n" + "2:\ttestb %%al,%%al\n\t" + "jne 1b" + :"=g" (res), "=&S" (d0), "=&a" (d1) + :"0" (0),"1" (s),"2" (c) + :"memory"); + return res; +} +EXPORT_SYMBOL(strrchr); +#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 |