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From 250962053fadd0911accad515802d9b957c9d019 Mon Sep 17 00:00:00 2001
From: Stefan Liebler <stli@linux.vnet.ibm.com>
Date: Thu, 8 Oct 2015 13:24:58 +0200
Subject: [PATCH 30/30] S390: Optimize memrchr.
upstream-commit-id: 798f5b4b5d24e5687dd55acc535954ed1d59c10c
https://www.sourceware.org/ml/libc-alpha/2015-07/msg00092.html
This patch provides optimized version of memrchr with the z13 vector
instructions.
ChangeLog:
* sysdeps/s390/multiarch/memrchr-c.c: New File.
* sysdeps/s390/multiarch/memrchr-vx.S: Likewise.
* sysdeps/s390/multiarch/memrchr.c: Likewise.
* sysdeps/s390/multiarch/Makefile
(sysdep_routines): Add memrchr functions.
* sysdeps/s390/multiarch/ifunc-impl-list-common.c
(__libc_ifunc_impl_list_common): Add ifunc test for memrchr.
---
sysdeps/s390/multiarch/Makefile | 3 +-
sysdeps/s390/multiarch/ifunc-impl-list.c | 2 +
sysdeps/s390/multiarch/memrchr-c.c | 25 +++++
sysdeps/s390/multiarch/memrchr-vx.S | 160 +++++++++++++++++++++++++++++++
sysdeps/s390/multiarch/memrchr.c | 28 ++++++
5 files changed, 217 insertions(+), 1 deletion(-)
create mode 100644 sysdeps/s390/multiarch/memrchr-c.c
create mode 100644 sysdeps/s390/multiarch/memrchr-vx.S
create mode 100644 sysdeps/s390/multiarch/memrchr.c
diff --git a/sysdeps/s390/multiarch/Makefile b/sysdeps/s390/multiarch/Makefile
index 929a545..0805b07 100644
--- a/sysdeps/s390/multiarch/Makefile
+++ b/sysdeps/s390/multiarch/Makefile
@@ -17,7 +17,8 @@ sysdep_routines += strlen strlen-vx strlen-c \
strcspn strcspn-vx strcspn-c \
memchr memchr-vx \
rawmemchr rawmemchr-vx rawmemchr-c \
- memccpy memccpy-vx memccpy-c
+ memccpy memccpy-vx memccpy-c \
+ memrchr memrchr-vx memrchr-c
endif
ifeq ($(subdir),wcsmbs)
diff --git a/sysdeps/s390/multiarch/ifunc-impl-list.c b/sysdeps/s390/multiarch/ifunc-impl-list.c
index 5ea258b..c235bdc 100644
--- a/sysdeps/s390/multiarch/ifunc-impl-list.c
+++ b/sysdeps/s390/multiarch/ifunc-impl-list.c
@@ -137,6 +137,8 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
IFUNC_VX_IMPL (wmemcmp);
+ IFUNC_VX_IMPL (memrchr);
+
#endif /* HAVE_S390_VX_ASM_SUPPORT */
return i;
diff --git a/sysdeps/s390/multiarch/memrchr-c.c b/sysdeps/s390/multiarch/memrchr-c.c
new file mode 100644
index 0000000..6a32861
--- /dev/null
+++ b/sysdeps/s390/multiarch/memrchr-c.c
@@ -0,0 +1,25 @@
+/* Default memrchr implementation for S/390.
+ Copyright (C) 2015 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 && !defined NOT_IN_libc
+# define MEMRCHR __memrchr_c
+
+# include <string.h>
+extern __typeof (__memrchr) __memrchr_c;
+# include <string/memrchr.c>
+#endif
diff --git a/sysdeps/s390/multiarch/memrchr-vx.S b/sysdeps/s390/multiarch/memrchr-vx.S
new file mode 100644
index 0000000..da6dbdf
--- /dev/null
+++ b/sysdeps/s390/multiarch/memrchr-vx.S
@@ -0,0 +1,160 @@
+/* Vector optimized 32/64 bit S/390 version of memrchr.
+ Copyright (C) 2015 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 && !defined NOT_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 && !defined NOT_IN_libc */
diff --git a/sysdeps/s390/multiarch/memrchr.c b/sysdeps/s390/multiarch/memrchr.c
new file mode 100644
index 0000000..6596067
--- /dev/null
+++ b/sysdeps/s390/multiarch/memrchr.c
@@ -0,0 +1,28 @@
+/* Multiple versions of memrchr.
+ Copyright (C) 2015 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 && !defined NOT_IN_libc
+# include <string.h>
+# include <ifunc-resolve.h>
+
+s390_vx_libc_ifunc (__memrchr)
+weak_alias (__memrchr, memrchr)
+
+#else
+# include <string/memrchr.c>
+#endif /* !(defined HAVE_S390_VX_ASM_SUPPORT && !defined NOT_IN_libc) */
--
2.3.0