[444] | 1 | /* Copyright (c) 2009 Xilinx, Inc. All rights reserved. |
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| 2 | |
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| 3 | Redistribution and use in source and binary forms, with or without |
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| 4 | modification, are permitted provided that the following conditions are |
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| 5 | met: |
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| 6 | |
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| 7 | 1. Redistributions source code must retain the above copyright notice, |
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| 8 | this list of conditions and the following disclaimer. |
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| 9 | |
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| 10 | 2. Redistributions in binary form must reproduce the above copyright |
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| 11 | notice, this list of conditions and the following disclaimer in the |
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| 12 | documentation and/or other materials provided with the distribution. |
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| 13 | |
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| 14 | 3. Neither the name of Xilinx nor the names of its contributors may be |
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| 15 | used to endorse or promote products derived from this software without |
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| 16 | specific prior written permission. |
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| 17 | |
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| 18 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS "AS |
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| 19 | IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
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| 20 | TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A |
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| 21 | PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
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| 22 | HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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| 23 | SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED |
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| 24 | TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
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| 25 | PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
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| 26 | LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
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| 27 | NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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| 28 | SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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| 29 | |
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| 30 | |
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| 31 | FUNCTION |
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| 32 | <<strlen>>---character string length |
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| 33 | |
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| 34 | INDEX |
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| 35 | strlen |
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| 36 | |
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| 37 | SYNOPSIS |
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| 38 | #include <string.h> |
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| 39 | size_t strlen(const char *<[str]>); |
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| 40 | |
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| 41 | DESCRIPTION |
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| 42 | The <<strlen>> function works out the length of the string |
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| 43 | starting at <<*<[str]>>> by counting chararacters until it |
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| 44 | reaches a <<NULL>> character. |
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| 45 | |
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| 46 | RETURNS |
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| 47 | <<strlen>> returns the character count. |
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| 48 | |
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| 49 | PORTABILITY |
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| 50 | <<strlen>> is ANSI C. |
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| 51 | |
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| 52 | <<strlen>> requires no supporting OS subroutines. |
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| 53 | |
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| 54 | QUICKREF |
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| 55 | strlen ansi pure |
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| 56 | */ |
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| 57 | |
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| 58 | #include <_ansi.h> |
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| 59 | #include <string.h> |
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| 60 | #include <limits.h> |
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| 61 | |
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| 62 | #define LBLOCKSIZE (sizeof (long)) |
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| 63 | #define UNALIGNED(X) ((long)X & (LBLOCKSIZE - 1)) |
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| 64 | |
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| 65 | #if LONG_MAX == 2147483647L |
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| 66 | #define DETECTNULL(X) (((X) - 0x01010101) & ~(X) & 0x80808080) |
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| 67 | #else |
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| 68 | #if LONG_MAX == 9223372036854775807L |
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| 69 | /* Nonzero if X (a long int) contains a NULL byte. */ |
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| 70 | #define DETECTNULL(X) (((X) - 0x0101010101010101) & ~(X) & 0x8080808080808080) |
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| 71 | #else |
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| 72 | #error long int is not a 32bit or 64bit type. |
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| 73 | #endif |
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| 74 | #endif |
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| 75 | |
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| 76 | #ifndef DETECTNULL |
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| 77 | #error long int is not a 32bit or 64bit byte |
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| 78 | #endif |
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| 79 | |
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| 80 | size_t |
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| 81 | strlen (const char *str) |
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| 82 | { |
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| 83 | |
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| 84 | #ifndef HAVE_HW_PCMP |
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| 85 | |
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| 86 | #if defined(PREFER_SIZE_OVER_SPEED) || defined(__OPTIMIZE_SIZE__) |
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| 87 | const char *start = str; |
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| 88 | |
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| 89 | while (*str) |
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| 90 | str++; |
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| 91 | |
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| 92 | return str - start; |
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| 93 | #else |
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| 94 | const char *start = str; |
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| 95 | unsigned long *aligned_addr; |
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| 96 | |
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| 97 | if (!UNALIGNED (str)) |
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| 98 | { |
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| 99 | /* If the string is word-aligned, we can check for the presence of |
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| 100 | a null in each word-sized block. */ |
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| 101 | aligned_addr = (unsigned long*)str; |
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| 102 | while (!DETECTNULL (*aligned_addr)) |
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| 103 | aligned_addr++; |
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| 104 | |
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| 105 | /* Once a null is detected, we check each byte in that block for a |
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| 106 | precise position of the null. */ |
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| 107 | str = (char*)aligned_addr; |
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| 108 | } |
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| 109 | |
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| 110 | while (*str) |
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| 111 | str++; |
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| 112 | return str - start; |
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| 113 | #endif /* not PREFER_SIZE_OVER_SPEED */ |
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| 114 | |
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| 115 | #else |
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| 116 | |
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| 117 | #include "mb_endian.h" |
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| 118 | |
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| 119 | asm volatile (" \n\ |
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| 120 | or r9, r0, r0 /* Index register */ \n\ |
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| 121 | check_alignment: \n\ |
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| 122 | andi r3, r5, 3 \n\ |
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| 123 | bnei r3, align_arg \n\ |
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| 124 | len_loop: \n" |
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| 125 | LOAD4BYTES("r3", "r5", "r9") |
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| 126 | " \n\ |
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| 127 | pcmpbf r4, r3, r0 \n\ |
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| 128 | bnei r4, end_len \n\ |
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| 129 | brid len_loop \n\ |
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| 130 | addik r9, r9, 4 \n\ |
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| 131 | end_len: \n\ |
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| 132 | lbu r3, r5, r9 \n\ |
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| 133 | beqi r3, done_len \n\ |
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| 134 | brid end_len \n\ |
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| 135 | addik r9, r9, 1 \n\ |
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| 136 | done_len: \n\ |
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| 137 | rtsd r15, 8 \n\ |
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| 138 | or r3, r0, r9 /* Return len */ \n\ |
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| 139 | align_arg: \n\ |
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| 140 | rsubik r10, r3, 4 \n\ |
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| 141 | align_loop: \n\ |
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| 142 | lbu r3, r5, r9 \n\ |
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| 143 | beqid r3, done_len \n\ |
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| 144 | addik r10, r10, -1 \n\ |
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| 145 | bneid r10, align_loop \n\ |
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| 146 | addik r9, r9, 1 \n\ |
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| 147 | bri len_loop"); |
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| 148 | |
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| 149 | #endif /* ! HAVE_HW_PCMP */ |
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| 150 | } |
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