1/* 2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 */ 8 9/* ARC700 has a relatively long pipeline and branch prediction, so we want 10 to avoid branches that are hard to predict. On the other hand, the 11 presence of the norm instruction makes it easier to operate on whole 12 words branch-free. */ 13 14#include <linux/linkage.h> 15 16ENTRY(strchr) 17 extb_s r1,r1 18 asl r5,r1,8 19 bmsk r2,r0,1 20 or r5,r5,r1 21 mov_s r3,0x01010101 22 breq.d r2,r0,.Laligned 23 asl r4,r5,16 24 sub_s r0,r0,r2 25 asl r7,r2,3 26 ld_s r2,[r0] 27#ifdef __LITTLE_ENDIAN__ 28 asl r7,r3,r7 29#else 30 lsr r7,r3,r7 31#endif 32 or r5,r5,r4 33 ror r4,r3 34 sub r12,r2,r7 35 bic_s r12,r12,r2 36 and r12,r12,r4 37 brne.d r12,0,.Lfound0_ua 38 xor r6,r2,r5 39 ld.a r2,[r0,4] 40 sub r12,r6,r7 41 bic r12,r12,r6 42#ifdef __LITTLE_ENDIAN__ 43 and r7,r12,r4 44 breq r7,0,.Loop ; For speed, we want this branch to be unaligned. 45 b .Lfound_char ; Likewise this one. 46#else 47 and r12,r12,r4 48 breq r12,0,.Loop ; For speed, we want this branch to be unaligned. 49 lsr_s r12,r12,7 50 bic r2,r7,r6 51 b.d .Lfound_char_b 52 and_s r2,r2,r12 53#endif 54; /* We require this code address to be unaligned for speed... */ 55.Laligned: 56 ld_s r2,[r0] 57 or r5,r5,r4 58 ror r4,r3 59; /* ... so that this code address is aligned, for itself and ... */ 60.Loop: 61 sub r12,r2,r3 62 bic_s r12,r12,r2 63 and r12,r12,r4 64 brne.d r12,0,.Lfound0 65 xor r6,r2,r5 66 ld.a r2,[r0,4] 67 sub r12,r6,r3 68 bic r12,r12,r6 69 and r7,r12,r4 70 breq r7,0,.Loop /* ... so that this branch is unaligned. */ 71 ; Found searched-for character. r0 has already advanced to next word. 72#ifdef __LITTLE_ENDIAN__ 73/* We only need the information about the first matching byte 74 (i.e. the least significant matching byte) to be exact, 75 hence there is no problem with carry effects. */ 76.Lfound_char: 77 sub r3,r7,1 78 bic r3,r3,r7 79 norm r2,r3 80 sub_s r0,r0,1 81 asr_s r2,r2,3 82 j.d [blink] 83 sub_s r0,r0,r2 84 85 .balign 4 86.Lfound0_ua: 87 mov r3,r7 88.Lfound0: 89 sub r3,r6,r3 90 bic r3,r3,r6 91 and r2,r3,r4 92 or_s r12,r12,r2 93 sub_s r3,r12,1 94 bic_s r3,r3,r12 95 norm r3,r3 96 add_s r0,r0,3 97 asr_s r12,r3,3 98 asl.f 0,r2,r3 99 sub_s r0,r0,r12 100 j_s.d [blink] 101 mov.pl r0,0 102#else /* BIG ENDIAN */ 103.Lfound_char: 104 lsr r7,r7,7 105 106 bic r2,r7,r6 107.Lfound_char_b: 108 norm r2,r2 109 sub_s r0,r0,4 110 asr_s r2,r2,3 111 j.d [blink] 112 add_s r0,r0,r2 113 114.Lfound0_ua: 115 mov_s r3,r7 116.Lfound0: 117 asl_s r2,r2,7 118 or r7,r6,r4 119 bic_s r12,r12,r2 120 sub r2,r7,r3 121 or r2,r2,r6 122 bic r12,r2,r12 123 bic.f r3,r4,r12 124 norm r3,r3 125 126 add.pl r3,r3,1 127 asr_s r12,r3,3 128 asl.f 0,r2,r3 129 add_s r0,r0,r12 130 j_s.d [blink] 131 mov.mi r0,0 132#endif /* ENDIAN */ 133END(strchr) 134