391 lines
7.7 KiB
C
391 lines
7.7 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Optimized string functions
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*
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* S390 version
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* Copyright IBM Corp. 2004
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* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
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*/
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#define IN_ARCH_STRING_C 1
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#include <linux/types.h>
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#include <linux/string.h>
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#include <linux/export.h>
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/*
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* Helper functions to find the end of a string
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*/
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static inline char *__strend(const char *s)
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{
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unsigned long e = 0;
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asm volatile(
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" lghi 0,0\n"
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"0: srst %[e],%[s]\n"
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" jo 0b\n"
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: [e] "+&a" (e), [s] "+&a" (s)
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:
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: "cc", "memory", "0");
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return (char *)e;
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}
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static inline char *__strnend(const char *s, size_t n)
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{
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const char *p = s + n;
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asm volatile(
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" lghi 0,0\n"
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"0: srst %[p],%[s]\n"
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" jo 0b\n"
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: [p] "+&d" (p), [s] "+&a" (s)
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:
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: "cc", "memory", "0");
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return (char *)p;
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}
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/**
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* strlen - Find the length of a string
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* @s: The string to be sized
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*
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* returns the length of @s
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*/
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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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return __strend(s) - s;
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}
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EXPORT_SYMBOL(strlen);
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#endif
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/**
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* strnlen - Find the length of a length-limited string
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* @s: The string to be sized
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* @n: The maximum number of bytes to search
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*
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* returns the minimum of the length of @s and @n
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*/
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#ifdef __HAVE_ARCH_STRNLEN
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size_t strnlen(const char *s, size_t n)
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{
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return __strnend(s, n) - s;
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}
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EXPORT_SYMBOL(strnlen);
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#endif
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/**
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* strcpy - Copy a %NUL terminated string
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* @dest: Where to copy the string to
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* @src: Where to copy the string from
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*
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* returns a pointer to @dest
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*/
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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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char *ret = dest;
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asm volatile(
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" lghi 0,0\n"
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"0: mvst %[dest],%[src]\n"
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" jo 0b\n"
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: [dest] "+&a" (dest), [src] "+&a" (src)
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:
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: "cc", "memory", "0");
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return ret;
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}
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EXPORT_SYMBOL(strcpy);
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#endif
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/**
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* strlcpy - Copy a %NUL terminated string into a sized buffer
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* @dest: Where to copy the string to
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* @src: Where to copy the string from
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* @size: size of destination buffer
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*
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* Compatible with *BSD: the result is always a valid
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* NUL-terminated string that fits in the buffer (unless,
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* of course, the buffer size is zero). It does not pad
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* out the result like strncpy() does.
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*/
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#ifdef __HAVE_ARCH_STRLCPY
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size_t strlcpy(char *dest, const char *src, size_t size)
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{
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size_t ret = __strend(src) - src;
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if (size) {
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size_t len = (ret >= size) ? size-1 : ret;
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dest[len] = '\0';
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memcpy(dest, src, len);
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}
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return ret;
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}
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EXPORT_SYMBOL(strlcpy);
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#endif
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/**
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* strncpy - Copy a length-limited, %NUL-terminated string
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* @dest: Where to copy the string to
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* @src: Where to copy the string from
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* @n: The maximum number of bytes to copy
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*
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* The result is not %NUL-terminated if the source exceeds
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* @n bytes.
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*/
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#ifdef __HAVE_ARCH_STRNCPY
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char *strncpy(char *dest, const char *src, size_t n)
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{
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size_t len = __strnend(src, n) - src;
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memset(dest + len, 0, n - len);
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memcpy(dest, src, len);
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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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/**
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* strcat - Append one %NUL-terminated string to another
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* @dest: The string to be appended to
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* @src: The string to append to it
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*
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* returns a pointer to @dest
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*/
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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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unsigned long dummy = 0;
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char *ret = dest;
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asm volatile(
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" lghi 0,0\n"
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"0: srst %[dummy],%[dest]\n"
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" jo 0b\n"
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"1: mvst %[dummy],%[src]\n"
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" jo 1b\n"
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: [dummy] "+&a" (dummy), [dest] "+&a" (dest), [src] "+&a" (src)
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:
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: "cc", "memory", "0");
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return ret;
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}
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EXPORT_SYMBOL(strcat);
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#endif
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/**
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* strlcat - Append a length-limited, %NUL-terminated string to another
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* @dest: The string to be appended to
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* @src: The string to append to it
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* @n: The size of the destination buffer.
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*/
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#ifdef __HAVE_ARCH_STRLCAT
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size_t strlcat(char *dest, const char *src, size_t n)
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{
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size_t dsize = __strend(dest) - dest;
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size_t len = __strend(src) - src;
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size_t res = dsize + len;
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if (dsize < n) {
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dest += dsize;
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n -= dsize;
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if (len >= n)
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len = n - 1;
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dest[len] = '\0';
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memcpy(dest, src, len);
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}
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return res;
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}
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EXPORT_SYMBOL(strlcat);
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#endif
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/**
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* strncat - Append a length-limited, %NUL-terminated string to another
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* @dest: The string to be appended to
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* @src: The string to append to it
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* @n: The maximum numbers of bytes to copy
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*
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* returns a pointer to @dest
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*
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* Note that in contrast to strncpy, strncat ensures the result is
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* terminated.
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*/
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#ifdef __HAVE_ARCH_STRNCAT
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char *strncat(char *dest, const char *src, size_t n)
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{
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size_t len = __strnend(src, n) - src;
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char *p = __strend(dest);
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p[len] = '\0';
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memcpy(p, src, len);
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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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/**
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* strcmp - Compare two strings
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* @s1: One string
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* @s2: Another string
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*
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* returns 0 if @s1 and @s2 are equal,
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* < 0 if @s1 is less than @s2
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* > 0 if @s1 is greater than @s2
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*/
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#ifdef __HAVE_ARCH_STRCMP
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int strcmp(const char *s1, const char *s2)
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{
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int ret = 0;
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asm volatile(
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" lghi 0,0\n"
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"0: clst %[s1],%[s2]\n"
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" jo 0b\n"
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" je 1f\n"
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" ic %[ret],0(%[s1])\n"
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" ic 0,0(%[s2])\n"
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" sr %[ret],0\n"
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"1:"
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: [ret] "+&d" (ret), [s1] "+&a" (s1), [s2] "+&a" (s2)
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:
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: "cc", "memory", "0");
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return ret;
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}
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EXPORT_SYMBOL(strcmp);
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#endif
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/**
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* strrchr - Find the last occurrence of a character in a string
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* @s: The string to be searched
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* @c: The character to search for
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*/
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#ifdef __HAVE_ARCH_STRRCHR
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char *strrchr(const char *s, int c)
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{
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ssize_t len = __strend(s) - s;
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do {
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if (s[len] == (char)c)
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return (char *)s + len;
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} while (--len >= 0);
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return NULL;
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}
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EXPORT_SYMBOL(strrchr);
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#endif
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static inline int clcle(const char *s1, unsigned long l1,
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const char *s2, unsigned long l2)
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{
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union register_pair r1 = { .even = (unsigned long)s1, .odd = l1, };
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union register_pair r3 = { .even = (unsigned long)s2, .odd = l2, };
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int cc;
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asm volatile(
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"0: clcle %[r1],%[r3],0\n"
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" jo 0b\n"
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" ipm %[cc]\n"
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" srl %[cc],28\n"
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: [cc] "=&d" (cc), [r1] "+&d" (r1.pair), [r3] "+&d" (r3.pair)
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:
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: "cc", "memory");
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return cc;
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}
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/**
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* strstr - Find the first substring in a %NUL terminated string
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* @s1: The string to be searched
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* @s2: The string to search for
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*/
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#ifdef __HAVE_ARCH_STRSTR
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char *strstr(const char *s1, const char *s2)
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{
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int l1, l2;
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l2 = __strend(s2) - s2;
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if (!l2)
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return (char *) s1;
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l1 = __strend(s1) - s1;
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while (l1-- >= l2) {
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int cc;
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cc = clcle(s1, l2, s2, l2);
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if (!cc)
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return (char *) s1;
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s1++;
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}
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return NULL;
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}
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EXPORT_SYMBOL(strstr);
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#endif
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/**
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* memchr - Find a character in an area of memory.
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* @s: The memory area
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* @c: The byte to search for
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* @n: The size of the area.
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*
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* returns the address of the first occurrence of @c, or %NULL
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* if @c is not found
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*/
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#ifdef __HAVE_ARCH_MEMCHR
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void *memchr(const void *s, int c, size_t n)
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{
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const void *ret = s + n;
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asm volatile(
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" lgr 0,%[c]\n"
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"0: srst %[ret],%[s]\n"
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" jo 0b\n"
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" jl 1f\n"
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" la %[ret],0\n"
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"1:"
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: [ret] "+&a" (ret), [s] "+&a" (s)
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: [c] "d" (c)
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: "cc", "memory", "0");
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return (void *) ret;
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}
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EXPORT_SYMBOL(memchr);
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#endif
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/**
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* memcmp - Compare two areas of memory
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* @s1: One area of memory
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* @s2: Another area of memory
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* @n: The size of the area.
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*/
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#ifdef __HAVE_ARCH_MEMCMP
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int memcmp(const void *s1, const void *s2, size_t n)
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{
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int ret;
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ret = clcle(s1, n, s2, n);
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if (ret)
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ret = ret == 1 ? -1 : 1;
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return ret;
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}
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EXPORT_SYMBOL(memcmp);
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#endif
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/**
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* memscan - Find a character in an area of memory.
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* @s: The memory area
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* @c: The byte to search for
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* @n: The size of the area.
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*
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* returns the address of the first occurrence of @c, or 1 byte past
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* the area if @c is not found
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*/
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#ifdef __HAVE_ARCH_MEMSCAN
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void *memscan(void *s, int c, size_t n)
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{
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const void *ret = s + n;
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asm volatile(
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" lgr 0,%[c]\n"
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"0: srst %[ret],%[s]\n"
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" jo 0b\n"
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: [ret] "+&a" (ret), [s] "+&a" (s)
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: [c] "d" (c)
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: "cc", "memory", "0");
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return (void *)ret;
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}
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EXPORT_SYMBOL(memscan);
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#endif
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