projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| 2e8a2de2 | 1 | /* Optimized strspn implementation for PowerPC64. |
| e65caf1f | 2 | |
| b168057a | 3 | Copyright (C) 2014-2015 Free Software Foundation, Inc. |
| e65caf1f VR |
4 | This file is part of the GNU C Library. |
| 5 | ||
| 6 | The GNU C Library is free software; you can redistribute it and/or | |
| 7 | modify it under the terms of the GNU Lesser General Public | |
| 8 | License as published by the Free Software Foundation; either | |
| 9 | version 2.1 of the License, or (at your option) any later version. | |
| 10 | ||
| 11 | The GNU C Library is distributed in the hope that it will be useful, | |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 14 | Lesser General Public License for more details. | |
| 15 | ||
| 16 | You should have received a copy of the GNU Lesser General Public | |
| 17 | License along with the GNU C Library; if not, see | |
| 18 | <http://www.gnu.org/licenses/>. */ | |
| 19 | ||
| 20 | /* size_t [r3] strspn (const char *string [r3], | |
| 21 | const char *needleAccept [r4] */ | |
| 22 | ||
| 23 | /* Performance gains are grabbed through following techniques: | |
| 24 | ||
| 25 | > hashing of needle. | |
| 26 | > hashing avoids scanning of duplicate entries in needle | |
| 27 | across the string. | |
| e65caf1f VR |
28 | > unrolling when scanning for character in string |
| 29 | across hash table. */ | |
| 30 | ||
| 31 | /* Algorithm is as below: | |
| 32 | 1. A empty hash table/dictionary is created comprising of | |
| 33 | 256 ascii character set | |
| 34 | 2. When hash entry is found in needle , the hash index | |
| 35 | is initialized to 1 | |
| 36 | 3. The string is scanned until end and for every character, | |
| 37 | its corresponding hash index is compared. | |
| 38 | 4. initial length of string (count) until first hit of | |
| 39 | accept needle to be found is set to 0 | |
| 40 | 4. If hash index is set to 1 for the index of string, | |
| 41 | count is returned. | |
| 42 | 5. Otherwise count is incremented and scanning continues | |
| 43 | until end of string. */ | |
| 44 | ||
| 45 | #include <sysdep.h> | |
| 46 | ||
| e65caf1f | 47 | EALIGN(strspn, 4, 0) |
| 2e8a2de2 AZ |
48 | CALL_MCOUNT 3 |
| 49 | ||
| 50 | /* PPC64 ELF ABI stack is aligned to 16 bytes. */ | |
| 51 | addi r9,r1,-256 | |
| 52 | /* Clear the table with 0 values */ | |
| 53 | li r6, 0 | |
| 54 | li r8, 4 | |
| 55 | mtctr r8 | |
| 56 | mr r10, r9 | |
| 57 | .align 4 | |
| 58 | L(zerohash): | |
| 59 | std r6, 0(r10) | |
| 60 | std r6, 8(r10) | |
| 61 | std r6, 16(r10) | |
| 62 | std r6, 24(r10) | |
| 63 | std r6, 32(r10) | |
| 64 | std r6, 40(r10) | |
| 65 | std r6, 48(r10) | |
| 66 | std r6, 56(r10) | |
| 67 | addi r10, r10, 64 | |
| 68 | bdnz L(zerohash) | |
| 69 | ||
| 70 | lbz r10,0(r4) | |
| e65caf1f VR |
71 | li r8, 1 /* r8=1, marker into hash if found in |
| 72 | needle */ | |
| e65caf1f VR |
73 | cmpdi cr7, r10, 0 /* accept needle is NULL */ |
| 74 | beq cr7, L(skipHashing) /* if needle is NULL, skip hashing */ | |
| 75 | ||
| 2e8a2de2 | 76 | .align 4 /* align section to 16 byte boundary */ |
| e65caf1f VR |
77 | L(hashing): |
| 78 | stbx r8, r9, r10 /* update hash with marker for the pivot of | |
| 79 | the needle */ | |
| 80 | lbzu r10, 1(r4) /* load needle into r10 and update to next */ | |
| 81 | cmpdi cr7, r10, 0 /* if needle is has reached NULL, continue */ | |
| 82 | bne cr7, L(hashing) /* loop to hash the needle */ | |
| 83 | ||
| 84 | L(skipHashing): | |
| 85 | li r10, 0 /* load counter = 0 */ | |
| 86 | b L(beginScan) | |
| 87 | ||
| 2e8a2de2 | 88 | .align 4 /* align section to 16 byte boundary */ |
| e65caf1f VR |
89 | L(scanUnroll): |
| 90 | lbzx r8, r9, r8 /* load r8 with hash value at index */ | |
| 91 | cmpwi cr7, r8, 0 /* if we hit marker in hash, we have found | |
| 92 | accept needle */ | |
| 93 | beq cr7, L(ret1stIndex) /* we have hit accept needle, return the | |
| 94 | count */ | |
| 95 | ||
| 96 | lbz r8, 1(r3) /* load string[1] into r8 */ | |
| 97 | addi r10, r10, 4 /* increment counter */ | |
| 98 | lbzx r8, r9, r8 /* load r8 with hash value at index */ | |
| 99 | cmpwi cr7, r8, 0 /* if we hit marker in hash, we have found | |
| 100 | accept needle */ | |
| 101 | beq cr7, L(ret2ndIndex) /* we have hit accept needle, return the | |
| 102 | count */ | |
| 103 | ||
| 104 | lbz r8, 2(r3) /* load string[2] into r8 */ | |
| 105 | lbzx r8, r9, r8 /* load r8 with hash value at index */ | |
| 106 | cmpwi cr7, r8, 0 /* if we hit marker in hash, we have found | |
| 107 | accept needle */ | |
| 108 | beq cr7, L(ret3rdIndex) /* we have hit accept needle, return the | |
| 109 | count */ | |
| 110 | ||
| 111 | lbz r8, 3(r3) /* load string[3] into r8 */ | |
| 112 | lbzx r8, r9, r8 /* load r8 with hash value at index */ | |
| 113 | addi r3, r3, 4 /* unroll factor , increment string by 4 */ | |
| 114 | cmpwi cr7, r8, 0 /* if we hit marker in hash, we have found | |
| 115 | accept needle */ | |
| 116 | beq cr7,L(ret4thIndex) /* we have hit accept needle, return the | |
| 117 | count */ | |
| 118 | ||
| 119 | L(beginScan): | |
| 120 | lbz r8, 0(r3) /* load string[0] into r8 */ | |
| 121 | addi r6, r10, 1 /* place holder for counter + 1 */ | |
| 122 | addi r5, r10, 2 /* place holder for counter + 2 */ | |
| 123 | addi r4, r10, 3 /* place holder for counter + 3 */ | |
| 124 | cmpdi cr7, r8, 0 /* if we hit marker in hash, we have found | |
| 125 | accept needle */ | |
| 126 | bne cr7, L(scanUnroll) /* continue scanning */ | |
| 127 | ||
| 128 | L(ret1stIndex): | |
| 129 | mr r3, r10 /* update r3 for return */ | |
| 130 | blr /* return */ | |
| 131 | ||
| 132 | L(ret2ndIndex): | |
| 133 | mr r3, r6 /* update r3 for return */ | |
| 134 | blr /* return */ | |
| 135 | ||
| 136 | L(ret3rdIndex): | |
| 137 | mr r3, r5 /* update r3 for return */ | |
| 138 | blr /* return */ | |
| 139 | ||
| 140 | L(ret4thIndex): | |
| 141 | mr r3, r4 /* update r3 for return */ | |
| 142 | blr /* done */ | |
| 143 | END(strspn) | |
| 144 | libc_hidden_builtin_def (strspn) |