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authorRoland McGrath <roland@gnu.org>1995-10-16 01:37:51 +0000
committerRoland McGrath <roland@gnu.org>1995-10-16 01:37:51 +0000
commit8f5ca04bc7fd53741d80117df992995ace8f6d2d (patch)
treee39c13fc198b22ec55647259a8080051988e8c69 /sysdeps/i386/stpcpy.S
parent5d82cf5c55f56ae10d3b0a205d1fcc7de1cf56a0 (diff)
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Sat Oct 14 02:52:36 1995 Ulrich Drepper <drepper@ipd.info.uni-karlsruhe.de>
* malloc/malloc.c (_malloc_internal): Performance fix. Move if statement out of loop. * stdio/_itoa.c, stdio/_itoa.h: Complete rewrite. Much faster implementation using GMP functions. Contributed by Torbjorn Granlund and Ulrich Drepper. * stdio/test_rdwr.c: Include <errno.h>. * sysdeps/i386/i586/Implies: New file. New highly optimized string functions for i[345]86. * sysdeps/i386/memchr.S, sysdeps/i386/memcmp.S: New files. * sysdeps/i386/stpcpy.S, sysdeps/i386/stpncpy.S: New files. * sysdeps/i386/strchr.S, sysdeps/i386/strcspn.S: New files. * sysdeps/i386/strpbrk.S, sysdeps/i386/strrchr.S: New files. * sysdeps/i386/strspn.S, sysdeps/i386/i486/strcat.S: New files. * sysdeps/i386/i486/strlen.S, sysdeps/i386/i586/strchr.S: New files. * sysdeps/i386/i586/strlen.S: New file. * sysdeps/i386/memchr.c: Removed. There is now an assembler version. * sysdeps/i386/i586/memcopy.h (WORD_COPY_BWD): Parameters did not correspond to used values. * sysdeps/unix/sysv/linux/nfs/nfs.h: New file. Simply a wrapper around a kernel header file. * sysdeps/unix/sysv/linux/Dist: Add it. * sysdeps/unix/sysv/linux/Makefile [$(subdir)=sunrpc] (headers): Likewise. * sysdeps/unix/sysv/linux/local_lim.h: Rewrite. Instead of defining ourself we use a kernel header file. * sysdeps/unix/sysv/linux/i386/sysdep.h (DO_CALL): Optimize system call handler for i586. * sysdeps/unix/sysv/linux/sys/param.h: Add copyright and clean up. Sat Oct 14 02:52:36 1995 Ulrich Drepper <drepper@ipd.info.uni-karlsruhe.de> * malloc/malloc.c (_malloc_internal): Performance fix. Move if statement out of loop. * stdio/_itoa.c, stdio/_itoa.h: Complete rewrite. Much faster implementation using GMP functions. Contributed by Torbjorn Granlund and Ulrich Drepper. * stdio/test_rdwr.c: Include <errno.h>. * sysdeps/i386/i586/Implies: New file. New highly optimized string functions for i[345]86. * sysdeps/i386/memchr.S, sysdeps/i386/memcmp.S: New files. * sysdeps/i386/stpcpy.S, sysdeps/i386/stpncpy.S: New files. * sysdeps/i386/strchr.S, sysdeps/i386/strcspn.S: New files. * sysdeps/i386/strpbrk.S, sysdeps/i386/strrchr.S: New files. * sysdeps/i386/strspn.S, sysdeps/i386/i486/strcat.S: New files. * sysdeps/i386/i486/strlen.S, sysdeps/i386/i586/strchr.S: New files. * sysdeps/i386/i586/strlen.S: New file. * sysdeps/i386/memchr.c: Removed. There is now an assembler version. * sysdeps/i386/i586/memcopy.h (WORD_COPY_BWD): Parameters did not correspond to used values. * sysdeps/unix/sysv/linux/nfs/nfs.h: New file. Simply a wrapper around a kernel header file. * sysdeps/unix/sysv/linux/Dist: Add it. * sysdeps/unix/sysv/linux/Makefile [$(subdir)=sunrpc] (headers): Likewise. * sysdeps/unix/sysv/linux/local_lim.h: Rewrite. Instead of defining ourself we use a kernel header file. * sysdeps/unix/sysv/linux/i386/sysdep.h (DO_CALL): Optimize system call handler for i586. * sysdeps/unix/sysv/linux/sys/param.h: Add copyright and clean up.
Diffstat (limited to 'sysdeps/i386/stpcpy.S')
-rw-r--r--sysdeps/i386/stpcpy.S87
1 files changed, 87 insertions, 0 deletions
diff --git a/sysdeps/i386/stpcpy.S b/sysdeps/i386/stpcpy.S
new file mode 100644
index 0000000000..f38a9089bc
--- /dev/null
+++ b/sysdeps/i386/stpcpy.S
@@ -0,0 +1,87 @@
+/* stpcpy -- copy SRC to DEST returning the address of the terminating '\0'
+ in DEST.
+For Intel 80x86, x>=3.
+Copyright (C) 1994, 1995 Free Software Foundation, Inc.
+Contributed by Ulrich Drepper (drepper@gnu.ai.mit.edu).
+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 Library General Public License as
+published by the Free Software Foundation; either version 2 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
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB. If
+not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA. */
+
+/* This function is defined neither in ANSI nor POSIX standards but is
+ also not invented here. */
+
+#include <sysdep.h>
+#include "asm-syntax.h"
+
+/*
+ INPUT PARAMETERS:
+ dest (sp + 4)
+ src (sp + 8)
+*/
+
+ .text
+ENTRY (__stpcpy)
+ movl 4(%esp), %eax /* load destination pointer */
+ movl 8(%esp), %ecx /* load source pointer */
+
+ subl %eax, %ecx /* magic: reduce number of loop variants
+ to one using addressing mode */
+
+ /* Here we would like to write
+
+ subl $4, %eax
+ ALIGN (4)
+
+ but the assembler is too smart and optimizes for the shortest
+ form where the number only needs one byte. But if we could
+ have the long form we would not need the alignment. */
+
+ .byte 0x81, 0xe8 /* This is `subl $0x00000004, %eax' */
+ .long 0x00000004
+
+ /* Four times unfolded loop with only one loop counter. This
+ is achieved by the use of index+base adressing mode. As the
+ loop counter we use the destination address because this is
+ also the result. */
+L1: addl $4, %eax /* increment loop counter */
+
+ movb (%eax,%ecx), %dl /* load current char */
+ movb %dl, (%eax) /* and store it */
+ testb %dl, %dl /* was it NUL? */
+ jz L2 /* yes, then exit */
+
+ movb 1(%eax,%ecx), %dl /* load current char */
+ movb %dl, 1(%eax) /* and store it */
+ testb %dl, %dl /* was it NUL? */
+ jz L3 /* yes, then exit */
+
+ movb 2(%eax,%ecx), %dl /* load current char */
+ movb %dl, 2(%eax) /* and store it */
+ testb %dl, %dl /* was it NUL? */
+ jz L4 /* yes, then exit */
+
+ movb 3(%eax,%ecx), %dl /* load current char */
+ movb %dl, 3(%eax) /* and store it */
+ testb %dl, %dl /* was it NUL? */
+ jnz L1 /* no, then continue loop */
+
+ incl %eax /* correct loop counter */
+L4: incl %eax
+L3: incl %eax
+L2:
+ ret
+
+weak_alias (__stpcpy, stpcpy)