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3492cdf017
Before: total: 21 errors, 0 warnings, 237 lines checked After: total: 0 errors, 0 warnings, 237 lines checked paolo@paolo-desktop:~/linux.trees.git$ md5sum /tmp/string_32.o.* c55d059ef1612b32a8bb2771a72ae0d5 /tmp/string_32.o.after c55d059ef1612b32a8bb2771a72ae0d5 /tmp/string_32.o.before Signed-off-by: Paolo Ciarrocchi <paolo.ciarrocchi@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
238 lines
4.6 KiB
C
238 lines
4.6 KiB
C
/*
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* Most of the string-functions are rather heavily hand-optimized,
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* see especially strsep,strstr,str[c]spn. They should work, but are not
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* very easy to understand. Everything is done entirely within the register
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* set, making the functions fast and clean. String instructions have been
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* used through-out, making for "slightly" unclear code :-)
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*
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* AK: On P4 and K7 using non string instruction implementations might be faster
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* for large memory blocks. But most of them are unlikely to be used on large
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* strings.
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*/
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#include <linux/string.h>
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#include <linux/module.h>
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#ifdef __HAVE_ARCH_STRCPY
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char *strcpy(char *dest, const char *src)
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{
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int d0, d1, d2;
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asm volatile("1:\tlodsb\n\t"
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"stosb\n\t"
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"testb %%al,%%al\n\t"
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"jne 1b"
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: "=&S" (d0), "=&D" (d1), "=&a" (d2)
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: "0" (src), "1" (dest) : "memory");
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return dest;
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}
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EXPORT_SYMBOL(strcpy);
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#endif
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#ifdef __HAVE_ARCH_STRNCPY
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char *strncpy(char *dest, const char *src, size_t count)
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{
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int d0, d1, d2, d3;
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asm volatile("1:\tdecl %2\n\t"
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"js 2f\n\t"
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"lodsb\n\t"
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"stosb\n\t"
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"testb %%al,%%al\n\t"
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"jne 1b\n\t"
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"rep\n\t"
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"stosb\n"
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"2:"
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: "=&S" (d0), "=&D" (d1), "=&c" (d2), "=&a" (d3)
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: "0" (src), "1" (dest), "2" (count) : "memory");
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return dest;
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}
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EXPORT_SYMBOL(strncpy);
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#endif
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#ifdef __HAVE_ARCH_STRCAT
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char *strcat(char *dest, const char *src)
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{
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int d0, d1, d2, d3;
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asm volatile("repne\n\t"
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"scasb\n\t"
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"decl %1\n"
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"1:\tlodsb\n\t"
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"stosb\n\t"
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"testb %%al,%%al\n\t"
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"jne 1b"
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: "=&S" (d0), "=&D" (d1), "=&a" (d2), "=&c" (d3)
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: "0" (src), "1" (dest), "2" (0), "3" (0xffffffffu) : "memory");
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return dest;
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}
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EXPORT_SYMBOL(strcat);
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#endif
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#ifdef __HAVE_ARCH_STRNCAT
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char *strncat(char *dest, const char *src, size_t count)
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{
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int d0, d1, d2, d3;
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asm volatile("repne\n\t"
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"scasb\n\t"
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"decl %1\n\t"
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"movl %8,%3\n"
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"1:\tdecl %3\n\t"
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"js 2f\n\t"
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"lodsb\n\t"
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"stosb\n\t"
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"testb %%al,%%al\n\t"
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"jne 1b\n"
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"2:\txorl %2,%2\n\t"
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"stosb"
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: "=&S" (d0), "=&D" (d1), "=&a" (d2), "=&c" (d3)
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: "0" (src), "1" (dest), "2" (0), "3" (0xffffffffu), "g" (count)
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: "memory");
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return dest;
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}
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EXPORT_SYMBOL(strncat);
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#endif
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#ifdef __HAVE_ARCH_STRCMP
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int strcmp(const char *cs, const char *ct)
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{
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int d0, d1;
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int res;
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asm volatile("1:\tlodsb\n\t"
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"scasb\n\t"
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"jne 2f\n\t"
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"testb %%al,%%al\n\t"
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"jne 1b\n\t"
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"xorl %%eax,%%eax\n\t"
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"jmp 3f\n"
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"2:\tsbbl %%eax,%%eax\n\t"
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"orb $1,%%al\n"
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"3:"
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: "=a" (res), "=&S" (d0), "=&D" (d1)
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: "1" (cs), "2" (ct)
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: "memory");
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return res;
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}
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EXPORT_SYMBOL(strcmp);
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#endif
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#ifdef __HAVE_ARCH_STRNCMP
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int strncmp(const char *cs, const char *ct, size_t count)
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{
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int res;
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int d0, d1, d2;
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asm volatile("1:\tdecl %3\n\t"
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"js 2f\n\t"
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"lodsb\n\t"
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"scasb\n\t"
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"jne 3f\n\t"
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"testb %%al,%%al\n\t"
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"jne 1b\n"
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"2:\txorl %%eax,%%eax\n\t"
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"jmp 4f\n"
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"3:\tsbbl %%eax,%%eax\n\t"
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"orb $1,%%al\n"
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"4:"
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: "=a" (res), "=&S" (d0), "=&D" (d1), "=&c" (d2)
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: "1" (cs), "2" (ct), "3" (count)
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: "memory");
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return res;
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}
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EXPORT_SYMBOL(strncmp);
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#endif
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#ifdef __HAVE_ARCH_STRCHR
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char *strchr(const char *s, int c)
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{
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int d0;
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char *res;
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asm volatile("movb %%al,%%ah\n"
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"1:\tlodsb\n\t"
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"cmpb %%ah,%%al\n\t"
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"je 2f\n\t"
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"testb %%al,%%al\n\t"
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"jne 1b\n\t"
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"movl $1,%1\n"
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"2:\tmovl %1,%0\n\t"
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"decl %0"
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: "=a" (res), "=&S" (d0)
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: "1" (s), "0" (c)
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: "memory");
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return res;
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}
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EXPORT_SYMBOL(strchr);
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#endif
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#ifdef __HAVE_ARCH_STRLEN
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size_t strlen(const char *s)
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{
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int d0;
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int res;
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asm volatile("repne\n\t"
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"scasb\n\t"
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"notl %0\n\t"
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"decl %0"
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: "=c" (res), "=&D" (d0)
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: "1" (s), "a" (0), "0" (0xffffffffu)
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: "memory");
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return res;
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}
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EXPORT_SYMBOL(strlen);
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#endif
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#ifdef __HAVE_ARCH_MEMCHR
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void *memchr(const void *cs, int c, size_t count)
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{
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int d0;
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void *res;
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if (!count)
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return NULL;
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asm volatile("repne\n\t"
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"scasb\n\t"
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"je 1f\n\t"
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"movl $1,%0\n"
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"1:\tdecl %0"
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: "=D" (res), "=&c" (d0)
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: "a" (c), "0" (cs), "1" (count)
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: "memory");
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return res;
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}
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EXPORT_SYMBOL(memchr);
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#endif
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#ifdef __HAVE_ARCH_MEMSCAN
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void *memscan(void *addr, int c, size_t size)
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{
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if (!size)
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return addr;
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asm volatile("repnz; scasb\n\t"
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"jnz 1f\n\t"
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"dec %%edi\n"
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"1:"
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: "=D" (addr), "=c" (size)
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: "0" (addr), "1" (size), "a" (c)
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: "memory");
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return addr;
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}
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EXPORT_SYMBOL(memscan);
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#endif
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#ifdef __HAVE_ARCH_STRNLEN
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size_t strnlen(const char *s, size_t count)
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{
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int d0;
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int res;
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asm volatile("movl %2,%0\n\t"
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"jmp 2f\n"
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"1:\tcmpb $0,(%0)\n\t"
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"je 3f\n\t"
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"incl %0\n"
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"2:\tdecl %1\n\t"
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"cmpl $-1,%1\n\t"
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"jne 1b\n"
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"3:\tsubl %2,%0"
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: "=a" (res), "=&d" (d0)
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: "c" (s), "1" (count)
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: "memory");
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return res;
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}
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EXPORT_SYMBOL(strnlen);
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#endif
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