projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| 78df0fcb AJ |
1 | /* strcspn (str, ss) -- Return the length of the initial segment of STR |
| 2 | which contains no characters from SS. | |
| 3 | For AMD x86-64. | |
| ee618985 UD |
4 | Copyright (C) 1994-1997, 2000, 2002, 2003, 2004, 2005 |
| 5 | Free Software Foundation, Inc. | |
| 78df0fcb AJ |
6 | This file is part of the GNU C Library. |
| 7 | Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>. | |
| 8 | Bug fixes by Alan Modra <Alan@SPRI.Levels.UniSA.Edu.Au>. | |
| 9 | Adopted for x86-64 by Andreas Jaeger <aj@suse.de>. | |
| 10 | ||
| 11 | The GNU C Library is free software; you can redistribute it and/or | |
| 12 | modify it under the terms of the GNU Lesser General Public | |
| 13 | License as published by the Free Software Foundation; either | |
| 14 | version 2.1 of the License, or (at your option) any later version. | |
| 15 | ||
| 16 | The GNU C Library is distributed in the hope that it will be useful, | |
| 17 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 18 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 19 | Lesser General Public License for more details. | |
| 20 | ||
| 21 | You should have received a copy of the GNU Lesser General Public | |
| 59ba27a6 PE |
22 | License along with the GNU C Library; if not, see |
| 23 | <http://www.gnu.org/licenses/>. */ | |
| 78df0fcb AJ |
24 | |
| 25 | #include <sysdep.h> | |
| 26 | #include "asm-syntax.h" | |
| 27 | ||
| 28 | /* BEWARE: `#ifdef strcspn' means that strcspn is redefined as `strpbrk' */ | |
| 29 | #define STRPBRK_P (defined strcspn) | |
| 30 | ||
| 31 | .text | |
| 32 | ENTRY (strcspn) | |
| 33 | ||
| 34 | movq %rdi, %rdx /* Save SRC. */ | |
| 35 | ||
| 36 | /* First we create a table with flags for all possible characters. | |
| 37 | For the ASCII (7bit/8bit) or ISO-8859-X character sets which are | |
| 38 | supported by the C string functions we have 256 characters. | |
| 39 | Before inserting marks for the stop characters we clear the whole | |
| 40 | table. */ | |
| 41 | movq %rdi, %r8 /* Save value. */ | |
| 42 | subq $256, %rsp /* Make space for 256 bytes. */ | |
| a5ee0b9e | 43 | cfi_adjust_cfa_offset(256) |
| ee618985 | 44 | movl $32, %ecx /* 32*8 bytes = 256 bytes. */ |
| 78df0fcb | 45 | movq %rsp, %rdi |
| ee618985 | 46 | xorl %eax, %eax /* We store 0s. */ |
| 78df0fcb AJ |
47 | cld |
| 48 | rep | |
| 49 | stosq | |
| 50 | ||
| 51 | movq %rsi, %rax /* Setup skipset. */ | |
| 52 | ||
| 53 | /* For understanding the following code remember that %rcx == 0 now. | |
| 54 | Although all the following instruction only modify %cl we always | |
| 55 | have a correct zero-extended 64-bit value in %rcx. */ | |
| 56 | ||
| 57 | .p2align 4 | |
| 58 | L(2): movb (%rax), %cl /* get byte from skipset */ | |
| 59 | testb %cl, %cl /* is NUL char? */ | |
| 60 | jz L(1) /* yes => start compare loop */ | |
| 61 | movb %cl, (%rsp,%rcx) /* set corresponding byte in skipset table */ | |
| 62 | ||
| 63 | movb 1(%rax), %cl /* get byte from skipset */ | |
| 64 | testb $0xff, %cl /* is NUL char? */ | |
| 65 | jz L(1) /* yes => start compare loop */ | |
| 66 | movb %cl, (%rsp,%rcx) /* set corresponding byte in skipset table */ | |
| 67 | ||
| 68 | movb 2(%rax), %cl /* get byte from skipset */ | |
| 69 | testb $0xff, %cl /* is NUL char? */ | |
| 70 | jz L(1) /* yes => start compare loop */ | |
| 71 | movb %cl, (%rsp,%rcx) /* set corresponding byte in skipset table */ | |
| 72 | ||
| 73 | movb 3(%rax), %cl /* get byte from skipset */ | |
| 74 | addq $4, %rax /* increment skipset pointer */ | |
| 75 | movb %cl, (%rsp,%rcx) /* set corresponding byte in skipset table */ | |
| 76 | testb $0xff, %cl /* is NUL char? */ | |
| 77 | jnz L(2) /* no => process next dword from skipset */ | |
| 78 | ||
| 79 | L(1): leaq -4(%rdx), %rax /* prepare loop */ | |
| 80 | ||
| 81 | /* We use a neat trick for the following loop. Normally we would | |
| 82 | have to test for two termination conditions | |
| 83 | 1. a character in the skipset was found | |
| 84 | and | |
| 85 | 2. the end of the string was found | |
| 86 | But as a sign that the character is in the skipset we store its | |
| 87 | value in the table. But the value of NUL is NUL so the loop | |
| 88 | terminates for NUL in every case. */ | |
| 89 | ||
| 90 | .p2align 4 | |
| 91 | L(3): addq $4, %rax /* adjust pointer for full loop round */ | |
| 92 | ||
| 93 | movb (%rax), %cl /* get byte from string */ | |
| 94 | cmpb %cl, (%rsp,%rcx) /* is it contained in skipset? */ | |
| 95 | je L(4) /* yes => return */ | |
| 96 | ||
| 97 | movb 1(%rax), %cl /* get byte from string */ | |
| 98 | cmpb %cl, (%rsp,%rcx) /* is it contained in skipset? */ | |
| 99 | je L(5) /* yes => return */ | |
| 100 | ||
| 101 | movb 2(%rax), %cl /* get byte from string */ | |
| 102 | cmpb %cl, (%rsp,%rcx) /* is it contained in skipset? */ | |
| 103 | jz L(6) /* yes => return */ | |
| 104 | ||
| 105 | movb 3(%rax), %cl /* get byte from string */ | |
| 106 | cmpb %cl, (%rsp,%rcx) /* is it contained in skipset? */ | |
| 107 | jne L(3) /* no => start loop again */ | |
| 108 | ||
| 109 | incq %rax /* adjust pointer */ | |
| 110 | L(6): incq %rax | |
| 111 | L(5): incq %rax | |
| 112 | ||
| 113 | L(4): addq $256, %rsp /* remove skipset */ | |
| 0e328c85 | 114 | cfi_adjust_cfa_offset(-256) |
| 78df0fcb | 115 | #if STRPBRK_P |
| ee618985 | 116 | xorl %edx,%edx |
| 78df0fcb AJ |
117 | orb %cl, %cl /* was last character NUL? */ |
| 118 | cmovzq %rdx, %rax /* Yes: return NULL */ | |
| 119 | #else | |
| 120 | subq %rdx, %rax /* we have to return the number of valid | |
| 121 | characters, so compute distance to first | |
| 122 | non-valid character */ | |
| 123 | #endif | |
| 124 | ret | |
| 125 | END (strcspn) | |
| 85dd1003 | 126 | libc_hidden_builtin_def (strcspn) |