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. | |
| 04277e02 | 4 | Copyright (C) 1994-2019 Free Software Foundation, Inc. |
| 78df0fcb AJ |
5 | This file is part of the GNU C Library. |
| 6 | Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>. | |
| 7 | Bug fixes by Alan Modra <Alan@SPRI.Levels.UniSA.Edu.Au>. | |
| 8 | Adopted for x86-64 by Andreas Jaeger <aj@suse.de>. | |
| 9 | ||
| 10 | The GNU C Library is free software; you can redistribute it and/or | |
| 11 | modify it under the terms of the GNU Lesser General Public | |
| 12 | License as published by the Free Software Foundation; either | |
| 13 | version 2.1 of the License, or (at your option) any later version. | |
| 14 | ||
| 15 | The GNU C Library is distributed in the hope that it will be useful, | |
| 16 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 18 | Lesser General Public License for more details. | |
| 19 | ||
| 20 | You should have received a copy of the GNU Lesser General Public | |
| 59ba27a6 PE |
21 | License along with the GNU C Library; if not, see |
| 22 | <http://www.gnu.org/licenses/>. */ | |
| 78df0fcb AJ |
23 | |
| 24 | #include <sysdep.h> | |
| 25 | #include "asm-syntax.h" | |
| 26 | ||
| 78df0fcb AJ |
27 | .text |
| 28 | ENTRY (strcspn) | |
| 29 | ||
| 30 | movq %rdi, %rdx /* Save SRC. */ | |
| 31 | ||
| 32 | /* First we create a table with flags for all possible characters. | |
| 33 | For the ASCII (7bit/8bit) or ISO-8859-X character sets which are | |
| 34 | supported by the C string functions we have 256 characters. | |
| 35 | Before inserting marks for the stop characters we clear the whole | |
| 36 | table. */ | |
| 37 | movq %rdi, %r8 /* Save value. */ | |
| 38 | subq $256, %rsp /* Make space for 256 bytes. */ | |
| a5ee0b9e | 39 | cfi_adjust_cfa_offset(256) |
| ee618985 | 40 | movl $32, %ecx /* 32*8 bytes = 256 bytes. */ |
| 78df0fcb | 41 | movq %rsp, %rdi |
| ee618985 | 42 | xorl %eax, %eax /* We store 0s. */ |
| 78df0fcb AJ |
43 | cld |
| 44 | rep | |
| 45 | stosq | |
| 46 | ||
| 47 | movq %rsi, %rax /* Setup skipset. */ | |
| 48 | ||
| 49 | /* For understanding the following code remember that %rcx == 0 now. | |
| 50 | Although all the following instruction only modify %cl we always | |
| 51 | have a correct zero-extended 64-bit value in %rcx. */ | |
| 52 | ||
| 53 | .p2align 4 | |
| 54 | L(2): movb (%rax), %cl /* get byte from skipset */ | |
| 55 | testb %cl, %cl /* is NUL char? */ | |
| 56 | jz L(1) /* yes => start compare loop */ | |
| 57 | movb %cl, (%rsp,%rcx) /* set corresponding byte in skipset table */ | |
| 58 | ||
| 59 | movb 1(%rax), %cl /* get byte from skipset */ | |
| 60 | testb $0xff, %cl /* is NUL char? */ | |
| 61 | jz L(1) /* yes => start compare loop */ | |
| 62 | movb %cl, (%rsp,%rcx) /* set corresponding byte in skipset table */ | |
| 63 | ||
| 64 | movb 2(%rax), %cl /* get byte from skipset */ | |
| 65 | testb $0xff, %cl /* is NUL char? */ | |
| 66 | jz L(1) /* yes => start compare loop */ | |
| 67 | movb %cl, (%rsp,%rcx) /* set corresponding byte in skipset table */ | |
| 68 | ||
| 69 | movb 3(%rax), %cl /* get byte from skipset */ | |
| 70 | addq $4, %rax /* increment skipset pointer */ | |
| 71 | movb %cl, (%rsp,%rcx) /* set corresponding byte in skipset table */ | |
| 72 | testb $0xff, %cl /* is NUL char? */ | |
| 73 | jnz L(2) /* no => process next dword from skipset */ | |
| 74 | ||
| 75 | L(1): leaq -4(%rdx), %rax /* prepare loop */ | |
| 76 | ||
| 77 | /* We use a neat trick for the following loop. Normally we would | |
| 78 | have to test for two termination conditions | |
| 79 | 1. a character in the skipset was found | |
| 80 | and | |
| 81 | 2. the end of the string was found | |
| 82 | But as a sign that the character is in the skipset we store its | |
| 83 | value in the table. But the value of NUL is NUL so the loop | |
| 84 | terminates for NUL in every case. */ | |
| 85 | ||
| 86 | .p2align 4 | |
| 87 | L(3): addq $4, %rax /* adjust pointer for full loop round */ | |
| 88 | ||
| 89 | movb (%rax), %cl /* get byte from string */ | |
| 90 | cmpb %cl, (%rsp,%rcx) /* is it contained in skipset? */ | |
| 91 | je L(4) /* yes => return */ | |
| 92 | ||
| 93 | movb 1(%rax), %cl /* get byte from string */ | |
| 94 | cmpb %cl, (%rsp,%rcx) /* is it contained in skipset? */ | |
| 95 | je L(5) /* yes => return */ | |
| 96 | ||
| 97 | movb 2(%rax), %cl /* get byte from string */ | |
| 98 | cmpb %cl, (%rsp,%rcx) /* is it contained in skipset? */ | |
| 99 | jz L(6) /* yes => return */ | |
| 100 | ||
| 101 | movb 3(%rax), %cl /* get byte from string */ | |
| 102 | cmpb %cl, (%rsp,%rcx) /* is it contained in skipset? */ | |
| 103 | jne L(3) /* no => start loop again */ | |
| 104 | ||
| 105 | incq %rax /* adjust pointer */ | |
| 106 | L(6): incq %rax | |
| 107 | L(5): incq %rax | |
| 108 | ||
| 109 | L(4): addq $256, %rsp /* remove skipset */ | |
| 0e328c85 | 110 | cfi_adjust_cfa_offset(-256) |
| 70fe2eb7 | 111 | #ifdef USE_AS_STRPBRK |
| ee618985 | 112 | xorl %edx,%edx |
| 78df0fcb AJ |
113 | orb %cl, %cl /* was last character NUL? */ |
| 114 | cmovzq %rdx, %rax /* Yes: return NULL */ | |
| 9c84384c | 115 | #else |
| 78df0fcb AJ |
116 | subq %rdx, %rax /* we have to return the number of valid |
| 117 | characters, so compute distance to first | |
| 118 | non-valid character */ | |
| 119 | #endif | |
| 120 | ret | |
| 121 | END (strcspn) | |
| 85dd1003 | 122 | libc_hidden_builtin_def (strcspn) |