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/strlen.c will be 33 used. */ 34#include <picolibc.h> 35#if !defined (__OPTIMIZE_SIZE__) && !defined (PREFER_SIZE_OVER_SPEED) \ 36 && !defined (__ARC_RF16__) 37 38#include "asm.h" 39 40#if defined(__ARC601__) || !defined (__ARC_BARREL_SHIFTER__) 41/* This code is optimized for the ARC601 pipeline without barrel shifter. */ 42 43ENTRY (strlen) 44 or r3,r0,7 45 ld r2,[r3,-7] 46 ld.a r6,[r3,-3] 47 mov r4,0x01010101 48 ; uses long immediate 49#ifdef __LITTLE_ENDIAN__ 50 bmsk.f 0,r0,1 51 mov_s r1,31 52 add3_s r1,r1,r0 53 bmsk r7,r4,r1 54 xor.ne r7,r7,r4 55 btst_s r0,2 56 ror r5,r4 57 sub r1,r2,r7 58 bic_s r1,r1,r2 59 mov.eq r7,r4 60 sub r12,r6,r7 61 bic r12,r12,r6 62 or.eq r12,r12,r1 63 and r12,r12,r5 64 brne r12,0,.Learly_end 65#else /* BIG ENDIAN */ 66 add.f r1,r4,30 ; r1 mod 31 := -1; clear carry 67 ror r5,r4 68 sub3 r7,r1,r0 69 btst_s r0,2 70 sub r1,r2,r4 71 bic_s r1,r1,r2 72 bmsk r1,r1,r7 73 sub r12,r6,r4 74 bic r12,r12,r6 75 bmsk.ne r12,r12,r7 76 or.eq r12,r12,r1 77 and r12,r12,r5 78 brne r12,0,.Learly_end 79#endif /* ENDIAN */ 80 81.Loop: 82 ld_s r2,[r3,4] 83 ld.a r6,[r3,8] 84 ; stall for load result 85 sub r1,r2,r4 86 bic_s r1,r1,r2 87 sub r12,r6,r4 88 bic r12,r12,r6 89 or_s r12,r12,r1 90 and r12,r12,r5 91 breq_s r12,0,.Loop 92.Lend: 93 and.f r1,r1,r5 94 sub.ne r3,r3,4 95#ifdef __LITTLE_ENDIAN__ 96 mov.eq r1,r12 97 btst_s r1,7 98 sub r0,r3,r0 99 add.eq r0,r0,1 100 bmsk.f 0,r1,15 101 add.eq r0,r0,1 102 bmsk.f 0,r1,23 103 j_s.d [blink] 104 add.eq r0,r0,1 105#else /* BIG ENDIAN */ 106#ifdef __OPTIMIZE_SIZE__ 1071: ldb_s r1,[r3] 108 breq_s r1,0,0f 109 ldb.a r1,[r3,1] 110 breq_s r1,0,0f 111 ldb.a r1,[r3,1] 112 breq_s r1,0,0f 113 add_s r3,r3,1 1140: j_s.d [blink] 115 sub r0,r3,r0 116 117#define SPECIAL_EARLY_END 118.Learly_end: 119 mov_s r3,r0 120 b_s 1b 121#elif 0 /* Need more information about pipeline to assess if this is faster. */ 122 mov.eq r2,r6 123 and r2,r2,r5 124 sub1 r2,r4,r2 125 mov.eq r1,r12 126 bic.f r1,r1,r2 127 sub r0,r3,r0 128 add.pl r0,r0,1 129 btst.pl r1,23 130 add.eq r0,r0,1 131 btst.eq r1,15 132 j_s.d [blink] 133 add.eq r0,r0,1 134#else /* !__OPTIMIZE_SIZE__ */ 135 /* Need carry clear here. */ 136 mov.eq r2,r6 1371: bmsk r1,r2,23 138 breq r1,r2,0f 139 bmsk r2,r1,15 140 breq.d r1,r2,0f 141 add_s r3,r3,1 142 cmp r2,0x100 143 add_s r3,r3,2 1440: j_s.d [blink] 145 sbc r0,r3,r0 146 147#define SPECIAL_EARLY_END 148.Learly_end: 149 sub_s.ne r1,r1,r1 150 mov_s r12,0 151 bset r12,r12,r7 152 sub1 r2,r2,r12 153 b.d .Lend 154 sub1.ne r6,r6,r12 155#endif /* !__OPTIMIZE_SIZE__ */ 156#endif /* ENDIAN */ 157 158#ifndef SPECIAL_EARLY_END 159 .balign 4 160.Learly_end: 161 b.d .Lend 162 sub_s.ne r1,r1,r1 163#endif /* !SPECIAL_EARLY_END */ 164ENDFUNC (strlen) 165#endif /* __ARC601__ || !__ARC_BARREL_SHIFTER__*/ 166 167#endif /* !__OPTIMIZE_SIZE__ && !PREFER_SIZE_OVER_SPEED */ 168
