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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 | /* SPDX-License-Identifier: GPL-2.0-only */ /* * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) */ /* ARC700 has a relatively long pipeline and branch prediction, so we want to avoid branches that are hard to predict. On the other hand, the presence of the norm instruction makes it easier to operate on whole words branch-free. */ #include <linux/linkage.h> ENTRY_CFI(strchr) extb_s r1,r1 asl r5,r1,8 bmsk r2,r0,1 or r5,r5,r1 mov_s r3,0x01010101 breq.d r2,r0,.Laligned asl r4,r5,16 sub_s r0,r0,r2 asl r7,r2,3 ld_s r2,[r0] #ifdef __LITTLE_ENDIAN__ asl r7,r3,r7 #else lsr r7,r3,r7 #endif or r5,r5,r4 ror r4,r3 sub r12,r2,r7 bic_s r12,r12,r2 and r12,r12,r4 brne.d r12,0,.Lfound0_ua xor r6,r2,r5 ld.a r2,[r0,4] sub r12,r6,r7 bic r12,r12,r6 #ifdef __LITTLE_ENDIAN__ and r7,r12,r4 breq r7,0,.Loop ; For speed, we want this branch to be unaligned. b .Lfound_char ; Likewise this one. #else and r12,r12,r4 breq r12,0,.Loop ; For speed, we want this branch to be unaligned. lsr_s r12,r12,7 bic r2,r7,r6 b.d .Lfound_char_b and_s r2,r2,r12 #endif ; /* We require this code address to be unaligned for speed... */ .Laligned: ld_s r2,[r0] or r5,r5,r4 ror r4,r3 ; /* ... so that this code address is aligned, for itself and ... */ .Loop: sub r12,r2,r3 bic_s r12,r12,r2 and r12,r12,r4 brne.d r12,0,.Lfound0 xor r6,r2,r5 ld.a r2,[r0,4] sub r12,r6,r3 bic r12,r12,r6 and r7,r12,r4 breq r7,0,.Loop /* ... so that this branch is unaligned. */ ; Found searched-for character. r0 has already advanced to next word. #ifdef __LITTLE_ENDIAN__ /* We only need the information about the first matching byte (i.e. the least significant matching byte) to be exact, hence there is no problem with carry effects. */ .Lfound_char: sub r3,r7,1 bic r3,r3,r7 norm r2,r3 sub_s r0,r0,1 asr_s r2,r2,3 j.d [blink] sub_s r0,r0,r2 .balign 4 .Lfound0_ua: mov r3,r7 .Lfound0: sub r3,r6,r3 bic r3,r3,r6 and r2,r3,r4 or_s r12,r12,r2 sub_s r3,r12,1 bic_s r3,r3,r12 norm r3,r3 add_s r0,r0,3 asr_s r12,r3,3 asl.f 0,r2,r3 sub_s r0,r0,r12 j_s.d [blink] mov.pl r0,0 #else /* BIG ENDIAN */ .Lfound_char: lsr r7,r7,7 bic r2,r7,r6 .Lfound_char_b: norm r2,r2 sub_s r0,r0,4 asr_s r2,r2,3 j.d [blink] add_s r0,r0,r2 .Lfound0_ua: mov_s r3,r7 .Lfound0: asl_s r2,r2,7 or r7,r6,r4 bic_s r12,r12,r2 sub r2,r7,r3 or r2,r2,r6 bic r12,r2,r12 bic.f r3,r4,r12 norm r3,r3 add.pl r3,r3,1 asr_s r12,r3,3 asl.f 0,r2,r3 add_s r0,r0,r12 j_s.d [blink] mov.mi r0,0 #endif /* ENDIAN */ END_CFI(strchr) |