MFp4: Pentium/Athlon-optimised implementation of wmemchr().

svn path=/head/; revision=112129
2003-03-12 03:55:01 +00:00 · 2003-03-12 03:55:01 +00:00 · 34d4e9132c · 2020-12-20 02:59:44 +00:00
commit 34d4e9132c
parent 46300030ec
2 changed files with 115 additions and 1 deletions
--- a/lib/libc/i386/string/Makefile.inc
+++ b/lib/libc/i386/string/Makefile.inc
@ -3,4 +3,4 @@

 MDSRCS+=bcmp.S bcopy.S bzero.S ffs.S index.S memchr.S memcmp.S memcpy.S \
 	memmove.S memset.S rindex.S strcat.S strchr.S strcmp.S strcpy.S \
-	strlen.S strncmp.S strrchr.S swab.S wcscmp.S
+	strlen.S strncmp.S strrchr.S swab.S wcscmp.S wmemchr.S
--- a/lib/libc/i386/string/wmemchr.S
+++ b/lib/libc/i386/string/wmemchr.S
@ -0,0 +1,114 @@
+/*-
+ * Copyright (c) 2003 Tim J. Robbins.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <machine/asm.h>
+__FBSDID("$FreeBSD$");
+
+/*
+ * wchar_t *
+ * wmemchr(const wchar_t *buf, wchar_t c, size_t n) --
+ *	Search the wide character array `buf', which has length `n',
+ *	the character `c', return a pointer to it if found, or NULL on
+ *	failure.
+ */
+ENTRY(wmemchr)
+	pushl	%edi
+	pushl	%ebx
+	movl	12(%esp),%edi		/* Buffer */
+	movl	16(%esp),%eax		/* Wide character */
+	movl	20(%esp),%ecx		/* Length of buffer */
+
+	/*
+	 * Search in chunks of 8 wide characters (32 bytes).
+	 */
+	movl	%ecx,%ebx
+	shrl	$3,%ecx
+	jz	small
+.p2align 4,0x90
+bigloop:cmpl	%eax,(%edi)
+	je	found
+	cmpl	%eax,4(%edi)
+	je	found4
+	cmpl	%eax,8(%edi)
+	je	found8
+	cmpl	%eax,12(%edi)
+	je	found12
+	cmpl	%eax,16(%edi)
+	je	found16
+	cmpl	%eax,20(%edi)
+	je	found20
+	cmpl	%eax,24(%edi)
+	je	found24
+	cmpl	%eax,28(%edi)
+	je	found28
+	leal	32(%edi),%edi
+	decl	%ecx
+	jnz	bigloop
+	jmp	small
+.p2align 2,0x90
+found:	movl	%edi,%eax
+	popl	%ebx
+	popl	%edi
+	ret
+.p2align 2,0x90
+found4:	leal	4(%edi),%edi
+	jmp	found
+.p2align 2,0x90
+found8:	leal	8(%edi),%edi
+	jmp	found
+.p2align 2,0x90
+found12:leal	12(%edi),%edi
+	jmp	found
+.p2align 2,0x90
+found16:leal	16(%edi),%edi
+	jmp	found
+.p2align 2,0x90
+found20:leal	20(%edi),%edi
+	jmp	found
+.p2align 2,0x90
+found24:leal	24(%edi),%edi
+	jmp	found
+.p2align 2,0x90
+found28:leal	28(%edi),%edi
+	jmp	found
+
+	/*
+	 * Search remaining part of string.
+	 */
+.p2align 2,0x90
+small:	movl	%ebx,%ecx
+	andl	$7,%ecx
+	jz	no
+smltop:	cmpl	%eax,(%edi)
+	je	found
+	leal	4(%edi),%edi
+	decl	%ecx
+	jnz	smltop
+.p2align 2,0x90
+no:	xorl	%eax,%eax
+	popl	%ebx
+	popl	%edi
+	ret