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390 lines
7.7 KiB
390 lines
7.7 KiB
// 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 ([email protected]) |
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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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