| /* Vector optimized 32/64 bit S/390 version of memrchr. |
| Copyright (C) 2015-2018 Free Software Foundation, Inc. |
| This file is part of the GNU C Library. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #if defined HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) |
| |
| # include "sysdep.h" |
| # include "asm-syntax.h" |
| |
| .text |
| |
| /* void *memrchr (const void *s, int c, size_t n) |
| Scans memory for character c backwards |
| and returns pointer to first c. |
| |
| Register usage: |
| -r0=tmp |
| -r1=tmp |
| -r2=s |
| -r3=c |
| -r4=n |
| -r5=s in loop |
| |
| -v16=part of s |
| -v17=index of found c |
| -v18=c replicated |
| -v20=permute pattern |
| */ |
| ENTRY(__memrchr_vx) |
| .machine "z13" |
| .machinemode "zarch_nohighgprs" |
| |
| # if !defined __s390x__ |
| llgfr %r4,%r4 |
| # endif /* !defined __s390x__ */ |
| clgije %r4,0,.Lnot_found |
| |
| vlvgb %v18,%r3,0 /* Generate vector which elements are all c. |
| If c > 255, c will be truncated. */ |
| vrepb %v18,%v18,0 |
| |
| llcr %r3,%r3 /* char c_char = (char) c. */ |
| |
| /* check byte n - 1. */ |
| llc %r0,-1(%r4,%r2) |
| slgfi %r4,1 |
| clrje %r0,%r3,.Lfound_end |
| jh .Lnot_found /* Return NULL if n is now 0. */ |
| |
| larl %r1,.Lpermute_mask /* Load permute mask. */ |
| vl %v20,0(%r1) |
| |
| /* check byte n - 2. */ |
| llc %r0,-1(%r4,%r2) |
| slgfi %r4,1 |
| clrje %r0,%r3,.Lfound_end |
| jh .Lnot_found /* Return NULL if n is now 0. */ |
| |
| clgijhe %r4,64,.Lloop64 /* If n >= 64 -> loop64. */ |
| |
| .Llt64: |
| /* Process n < 64 bytes. */ |
| clgijl %r4,16,.Llt16 /* Jump away if n < 16. */ |
| aghi %r4,-16 |
| vl %v16,0(%r4,%r2) |
| vfeebs %v17,%v16,%v18 |
| jno .Lfound0 |
| clgijl %r4,16,.Llt16 |
| aghi %r4,-16 |
| vl %v16,0(%r4,%r2) |
| vfeebs %v17,%v16,%v18 |
| jno .Lfound0 |
| clgijl %r4,16,.Llt16 |
| aghi %r4,-16 |
| vl %v16,0(%r4,%r2) |
| vfeebs %v17,%v16,%v18 |
| jno .Lfound0 |
| .Llt16: |
| clgfi %r4,0 /* if remaining bytes == 0, return NULL. */ |
| locghie %r2,0 |
| ber %r14 |
| |
| aghi %r4,-1 /* vll needs highest index. */ |
| vll %v16,%r4,0(%r2) /* Load remaining bytes. */ |
| |
| /* Right-shift of v16 to mask bytes after highest index. */ |
| lhi %r0,15 |
| slr %r0,%r4 /* Compute byte count for vector shift right. */ |
| sll %r0,3 /* Convert to bit count. */ |
| vlvgb %v17,%r0,7 |
| vsrlb %v16,%v16,%v17 /* Vector shift right by byte by number of bytes |
| specified in bits 1-4 of byte 7 in v17. */ |
| j .Lfound_permute |
| |
| .Lfound48: |
| aghi %r4,16 |
| .Lfound32: |
| aghi %r4,16 |
| .Lfound16: |
| aghi %r4,16 |
| .Lfound0: |
| la %r2,0(%r4,%r2) /* Set pointer to start of v16. */ |
| lghi %r4,15 /* Set highest index in v16 to last index. */ |
| .Lfound_permute: |
| /* Search for a c in v16 in reversed byte order. v16 contains %r4 + 1 |
| bytes. If v16 was not fully loaded, the bytes are already |
| right shifted, so that the bytes in v16 can simply be reversed. */ |
| vperm %v16,%v16,%v16,%v20 /* Permute v16 to reversed order. */ |
| vfeeb %v16,%v16,%v18 /* Find c in reversed v16. */ |
| vlgvb %r1,%v16,7 /* Index of c or 16 if not found. */ |
| |
| /* Return NULL if there is no c in loaded bytes. */ |
| clrjh %r1,%r4,.Lnot_found |
| |
| slgr %r4,%r1 |
| .Lfound_end: |
| la %r2,0(%r4,%r2) /* Return pointer to c. */ |
| br %r14 |
| |
| .Lnot_found: |
| lghi %r2,0 |
| br %r14 |
| |
| .Lpermute_mask: |
| .byte 0x0F,0x0E,0x0D,0x0C,0x0B,0x0A,0x09,0x08 |
| .byte 0x07,0x06,0x05,0x04,0x03,0x02,0x01,0x00 |
| |
| .Lloop64: |
| aghi %r4,-64 |
| vl %v16,48(%r4,%r2) /* Load 16bytes of memory area. */ |
| vfeebs %v17,%v16,%v18 /* Find c. */ |
| jno .Lfound48 /* Jump away if c was found. */ |
| vl %v16,32(%r4,%r2) |
| vfeebs %v17,%v16,%v18 |
| jno .Lfound32 |
| vl %v16,16(%r4,%r2) |
| vfeebs %v17,%v16,%v18 |
| jno .Lfound16 |
| vl %v16,0(%r4,%r2) |
| vfeebs %v17,%v16,%v18 |
| jno .Lfound0 |
| |
| clgijhe %r4,64,.Lloop64 /* If n >= 64 -> loop64. */ |
| j .Llt64 |
| END(__memrchr_vx) |
| #endif /* HAVE_S390_VX_ASM_SUPPORT && IS_IN (libc) */ |
