| /* |
| * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| */ |
| |
| /* 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 <asm/linkage.h> |
| |
| ARC_ENTRY 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 |
| and r7,r12,r4 |
| breq r7,0,.Loop ; For speed, we want this branch to be unaligned. |
| b .Lfound_char ; Likewise this one. |
| ; /* 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 |
| 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 */ |
| ARC_EXIT strchr |