1/* 2 Copyright (c) 2015-2024, Synopsys, Inc. All rights reserved. 3 4 Redistribution and use in source and binary forms, with or without 5 modification, are permitted provided that the following conditions are met: 6 7 1) Redistributions of source code must retain the above copyright notice, 8 this list of conditions and the following disclaimer. 9 10 2) Redistributions in binary form must reproduce the above copyright notice, 11 this list of conditions and the following disclaimer in the documentation 12 and/or other materials provided with the distribution. 13 14 3) Neither the name of the Synopsys, Inc., nor the names of its contributors 15 may be used to endorse or promote products derived from this software 16 without specific prior written permission. 17 18 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 19 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 22 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 24 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 25 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 26 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 27 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 28 POSSIBILITY OF SUCH DAMAGE. 29*/ 30 31/* This implementation is optimized for performance. For code size a generic 32 implementation of this function from newlib/libc/string/strchr.c will be 33 used. */ 34#include <picolibc.h> 35 36#if !defined (__OPTIMIZE_SIZE__) && !defined (PREFER_SIZE_OVER_SPEED) \ 37 && !defined (__ARC_RF16__) 38 39/* ARC700 has a relatively long pipeline and branch prediction, so we want 40 to avoid branches that are hard to predict. On the other hand, the 41 presence of the norm instruction makes it easier to operate on whole 42 words branch-free. */ 43#include "asm.h" 44 45#if (defined (__ARC700__) || defined (__ARCEM__) || defined (__ARCHS__)) \ 46 && defined (__ARC_NORM__) && defined (__ARC_BARREL_SHIFTER__) 47 48ENTRY (strchr) 49 extb_s r1,r1 50 asl r5,r1,8 51 bmsk r2,r0,1 52 or r5,r5,r1 53 mov_s r3,0x01010101 54 breq.d r2,r0,.Laligned 55 asl r4,r5,16 56 sub_s r0,r0,r2 57 asl r7,r2,3 58 ld_s r2,[r0] 59#ifdef __LITTLE_ENDIAN__ 60 asl r7,r3,r7 61#else 62 lsr r7,r3,r7 63#endif 64 or r5,r5,r4 65 ror r4,r3 66 sub r12,r2,r7 67 bic_s r12,r12,r2 68 and r12,r12,r4 69 brne.d r12,0,.Lfound0_ua 70 xor r6,r2,r5 71 ld.a r2,[r0,4] 72 sub r12,r6,r7 73 bic r12,r12,r6 74#ifdef __LITTLE_ENDIAN__ 75 and r7,r12,r4 76 breq r7,0,.Loop ; For speed, we want this branch to be unaligned. 77 b_l .Lfound_char ; Likewise this one. 78#else 79 and r12,r12,r4 80 breq_l r12,0,.Loop ; For speed, we want this branch to be unaligned. 81 lsr_s r12,r12,7 82 bic r2,r7,r6 83 b.d .Lfound_char_b 84 and_s r2,r2,r12 85#endif 86; /* We require this code address to be unaligned for speed... */ 87.Laligned: 88 ld_s r2,[r0] 89 or r5,r5,r4 90 ror r4,r3 91; /* ... so that this code address is aligned, for itself and ... */ 92.Loop: 93 sub r12,r2,r3 94 bic_s r12,r12,r2 95 and r12,r12,r4 96 brne.d r12,0,.Lfound0 97 xor r6,r2,r5 98 ld.a r2,[r0,4] 99 sub r12,r6,r3 100 bic r12,r12,r6 101 and r7,r12,r4 102 breq r7,0,.Loop /* ... so that this branch is unaligned. */ 103 ; Found searched-for character. r0 has already advanced to next word. 104#ifdef __LITTLE_ENDIAN__ 105/* We only need the information about the first matching byte 106 (i.e. the least significant matching byte) to be exact, 107 hence there is no problem with carry effects. */ 108.Lfound_char: 109 sub r3,r7,1 110 bic r3,r3,r7 111 norm r2,r3 112 sub_s r0,r0,1 113 asr_s r2,r2,3 114 j_l.d [blink] 115 sub_s r0,r0,r2 116 117 .balign 4 118.Lfound0_ua: 119 mov_l r3,r7 120.Lfound0: 121 sub r3,r6,r3 122 bic r3,r3,r6 123 and r2,r3,r4 124 or_s r12,r12,r2 125 sub_s r3,r12,1 126 bic_s r3,r3,r12 127 norm r3,r3 128 add_s r0,r0,3 129 asr_s r12,r3,3 130 asl.f 0,r2,r3 131 sub_s r0,r0,r12 132 j_s.d [blink] 133 mov.pl r0,0 134#else /* BIG ENDIAN */ 135.Lfound_char: 136 lsr r7,r7,7 137 138 bic r2,r7,r6 139.Lfound_char_b: 140 norm r2,r2 141 sub_s r0,r0,4 142 asr_s r2,r2,3 143 j_l.d [blink] 144 add_s r0,r0,r2 145 146.Lfound0_ua: 147 mov_s r3,r7 148.Lfound0: 149 asl_s r2,r2,7 150 or r7,r6,r4 151 bic_s r12,r12,r2 152 sub r2,r7,r3 153 or r2,r2,r6 154 bic r12,r2,r12 155 bic.f r3,r4,r12 156 norm r3,r3 157 158 add.pl r3,r3,1 159 asr_s r12,r3,3 160 asl.f 0,r2,r3 161 add_s r0,r0,r12 162 j_s.d [blink] 163 mov.mi r0,0 164#endif /* ENDIAN */ 165ENDFUNC (strchr) 166#endif /* (__ARC700__ || __ARCEM__ || __ARCHS__) && __ARC_NORM__ 167 && __ARC_BARREL_SHIFTER__ */ 168 169#endif /* !__OPTIMIZE_SIZE__ && !PREFER_SIZE_OVER_SPEED */ 170
