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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/i486/strcat.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/i486/strcat.S')
-rw-r--r--sysdeps/i386/i486/strcat.S260
1 files changed, 260 insertions, 0 deletions
diff --git a/sysdeps/i386/i486/strcat.S b/sysdeps/i386/i486/strcat.S
new file mode 100644
index 0000000000..e3d2181bdb
--- /dev/null
+++ b/sysdeps/i386/i486/strcat.S
@@ -0,0 +1,260 @@
+/* strcat(dest, src) -- Append SRC on the end of DEST.
+For Intel 80x86, x>=4.
+Copyright (C) 1994, 1995 Free Software Foundation, Inc.
+Contributed by Ulrich Drepper <drepper@ipd.info.uni-karlsruhe.de>.
+Optimised a little by Alan Modra <Alan@SPRI.Levels.UniSA.Edu.Au>
+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.  */
+
+#include <sysdep.h>
+#include "asm-syntax.h"
+
+/*
+   INPUT PARAMETERS:
+   dest		(sp + 4)
+   src		(sp + 8)
+*/
+
+	.text
+ENTRY (strcat)
+	pushl %edi		/* Save callee-safe register.  */
+
+	movl 12(%esp), %ecx	/* load source pointer */
+	movl 8(%esp), %edx	/* load destination pointer */
+
+	testb $0xff, (%ecx)	/* Is source string empty? */
+	jz L8			/* yes => return */
+
+	/* Test the first bytes separately until destination is aligned.  */
+	testb $3, %edx		/* destination pointer aligned? */
+	jz L1			/* yes => begin scan loop */
+	testb $0xff, (%edx)	/* is end of string? */
+	jz L2			/* yes => start appending */
+	incl %edx		/* increment source pointer */
+
+	testb $3, %edx		/* destination pointer aligned? */
+	jz L1			/* yes => begin scan loop */
+	testb $0xff, (%edx)	/* is end of string? */
+	jz L2			/* yes => start appending */
+	incl %edx		/* increment source pointer */
+
+	testb $3, %edx		/* destination pointer aligned? */
+	jz L1			/* yes => begin scan loop */
+	testb $0xff, (%edx)	/* is end of string? */
+	jz L2			/* yes => start appending */
+	incl %edx		/* increment source pointer */
+
+	/* Now we are aligned.  Begin scan loop.  */
+	jmp L1
+
+	ALIGN(4)
+
+L4:	addl $16,%edx		/* increment destination pointer for round */
+
+L1:	movl (%edx), %eax	/* get word (= 4 bytes) in question */
+	movl $0xfefefeff, %edi	/* magic value */
+
+	/* If you compare this with the algorithm in memchr.S you will
+	   notice that here is an `xorl' statement missing.  But you must
+	   not forget that we are looking for C == 0 and `xorl $0, %eax'
+	   is a no-op.  */
+
+	addl %eax, %edi		/* add the magic value to the word.  We get
+				   carry bits reported for each byte which
+				   is *not* 0 */
+
+	/* According to the algorithm we had to reverse the effect of the
+	   XOR first and then test the overflow bits.  But because the
+	   following XOR would destroy the carry flag and it would (in a
+	   representation with more than 32 bits) not alter then last
+	   overflow, we can now test this condition.  If no carry is signaled
+	   no overflow must have occured in the last byte => it was 0.	*/
+	jnc L3
+
+	/* We are only interested in carry bits that change due to the
+	   previous add, so remove original bits */
+	xorl %eax, %edi		/* ((word^charmask)+magic)^(word^charmask) */
+
+	/* Now test for the other three overflow bits.  */
+	orl $0xfefefeff, %edi	/* set all non-carry bits */
+	incl %edi		/* add 1: if one carry bit was *not* set
+				   the addition will not result in 0.  */
+
+	/* If at least one byte of the word is C we don't get 0 in %ecx.  */
+	jnz L3
+
+	movl 4(%edx), %eax	/* get word from source */
+	movl $0xfefefeff, %edi	/* magic value */
+	addl %eax, %edi		/* add the magic value to the word.  We get
+				   carry bits reported for each byte which
+				   is *not* 0 */
+	jnc L5			/* highest byte is C => stop copying */
+	xorl %eax, %edi		/* ((word^charmask)+magic)^(word^charmask) */
+	orl $0xfefefeff, %edi	/* set all non-carry bits */
+	incl %edi		/* add 1: if one carry bit was *not* set
+				   the addition will not result in 0.  */
+	jnz L5			/* one byte is NUL => stop copying */
+
+	movl 8(%edx), %eax	/* get word from source */
+	movl $0xfefefeff, %edi	/* magic value */
+	addl %eax, %edi		/* add the magic value to the word.  We get
+				   carry bits reported for each byte which
+				   is *not* 0 */
+	jnc L6			/* highest byte is C => stop copying */
+	xorl %eax, %edi		/* ((word^charmask)+magic)^(word^charmask) */
+	orl $0xfefefeff, %edi	/* set all non-carry bits */
+	incl %edi		/* add 1: if one carry bit was *not* set
+				   the addition will not result in 0.  */
+	jnz L6			/* one byte is NUL => stop copying */
+
+	movl 12(%edx), %eax	/* get word from source */
+	movl $0xfefefeff, %edi	/* magic value */
+	addl %eax, %edi		/* add the magic value to the word.  We get
+				   carry bits reported for each byte which
+				   is *not* 0 */
+	jnc L7			/* highest byte is C => stop copying */
+	xorl %eax, %edi		/* ((word^charmask)+magic)^(word^charmask) */
+	orl $0xfefefeff, %edi	/* set all non-carry bits */
+	incl %edi		/* add 1: if one carry bit was *not* set
+				   the addition will not result in 0.  */
+	jz L4			/* no byte is NUL => carry on copying */
+
+L7:	addl $4, %edx		/* adjust source pointer */
+L6:	addl $4, %edx
+L5:	addl $4, %edx
+
+L3:	testb %al, %al		/* is first byte NUL? */
+	jz L2			/* yes => start copying */
+	incl %edx		/* increment source pointer */
+
+	testb %ah, %ah		/* is second byte NUL? */
+	jz L2			/* yes => start copying */
+	incl %edx		/* increment source pointer */
+
+	testl $0xff0000, %eax	/* is third byte NUL? */
+	jz L2			/* yes => start copying */
+	incl %edx		/* increment source pointer */
+
+L2:	subl %ecx, %edx		/* reduce number of loop variants */
+
+	/* Now we have to align the source pointer.  */
+	testb $3, %ecx		/* pointer correctly aligned? */
+	jz L29			/* yes => start copy loop */
+	movb (%ecx), %al	/* get first byte */
+	movb %al, (%ecx,%edx)	/* and store it */
+	andl %al, %al		/* is byte NUL? */
+	jz L8			/* yes => return */
+	incl %ecx		/* increment pointer */
+
+	testb $3, %ecx		/* pointer correctly aligned? */
+	jz L29			/* yes => start copy loop */
+	movb (%ecx), %al	/* get first byte */
+	movb %al, (%ecx,%edx)	/* and store it */
+	andl %al, %al		/* is byte NUL? */
+	jz L8			/* yes => return */
+	incl %ecx		/* increment pointer */
+
+	testb $3, %ecx		/* pointer correctly aligned? */
+	jz L29			/* yes => start copy loop */
+	movb (%ecx), %al	/* get first byte */
+	movb %al, (%ecx,%edx)	/* and store it */
+	andl %al, %al		/* is byte NUL? */
+	jz L8			/* yes => return */
+	incl %ecx		/* increment pointer */
+
+	/* Now we are aligned.  */
+	jmp L29			/* start copy loop */
+
+	ALIGN(4)
+
+L28:	movl %eax, 12(%ecx,%edx)/* store word at destination */
+	addl $16, %ecx		/* adjust pointer for full round */
+
+L29:	movl (%ecx), %eax	/* get word from source */
+	movl $0xfefefeff, %edi	/* magic value */
+	addl %eax, %edi		/* add the magic value to the word.  We get
+				   carry bits reported for each byte which
+				   is *not* 0 */
+	jnc L9			/* highest byte is C => stop copying */
+	xorl %eax, %edi		/* ((word^charmask)+magic)^(word^charmask) */
+	orl $0xfefefeff, %edi	/* set all non-carry bits */
+	incl %edi		/* add 1: if one carry bit was *not* set
+				   the addition will not result in 0.  */
+	jnz L9			/* one byte is NUL => stop copying */
+	movl %eax, (%ecx,%edx)	/* store word to destination */
+
+	movl 4(%ecx), %eax	/* get word from source */
+	movl $0xfefefeff, %edi	/* magic value */
+	addl %eax, %edi		/* add the magic value to the word.  We get
+				   carry bits reported for each byte which
+				   is *not* 0 */
+	jnc L91			/* highest byte is C => stop copying */
+	xorl %eax, %edi		/* ((word^charmask)+magic)^(word^charmask) */
+	orl $0xfefefeff, %edi	/* set all non-carry bits */
+	incl %edi		/* add 1: if one carry bit was *not* set
+				   the addition will not result in 0.  */
+	jnz L91			/* one byte is NUL => stop copying */
+	movl %eax, 4(%ecx,%edx)	/* store word to destination */
+
+	movl 8(%ecx), %eax	/* get word from source */
+	movl $0xfefefeff, %edi	/* magic value */
+	addl %eax, %edi		/* add the magic value to the word.  We get
+				   carry bits reported for each byte which
+				   is *not* 0 */
+	jnc L92			/* highest byte is C => stop copying */
+	xorl %eax, %edi		/* ((word^charmask)+magic)^(word^charmask) */
+	orl $0xfefefeff, %edi	/* set all non-carry bits */
+	incl %edi		/* add 1: if one carry bit was *not* set
+				   the addition will not result in 0.  */
+	jnz L92			/* one byte is NUL => stop copying */
+	movl %eax, 8(%ecx,%edx)	/* store word to destination */
+
+	movl 12(%ecx), %eax	/* get word from source */
+	movl $0xfefefeff, %edi	/* magic value */
+	addl %eax, %edi		/* add the magic value to the word.  We get
+				   carry bits reported for each byte which
+				   is *not* 0 */
+	jnc L93			/* highest byte is C => stop copying */
+	xorl %eax, %edi		/* ((word^charmask)+magic)^(word^charmask) */
+	orl $0xfefefeff, %edi	/* set all non-carry bits */
+	incl %edi		/* add 1: if one carry bit was *not* set
+				   the addition will not result in 0.  */
+	jz L28			/* no is NUL => carry on copying */
+
+L93:	addl $4, %ecx		/* adjust pointer */
+L92:	addl $4, %ecx
+L91:	addl $4, %ecx
+
+L9:	movb %al, (%ecx,%edx)	/* store first byte of last word */
+	orb %al, %al		/* is it NUL? */
+	jz L8			/* yes => return */
+
+	movb %ah, 1(%ecx,%edx)	/* store second byte of last word */
+	orb %ah, %ah		/* is it NUL? */
+	jz L8			/* yes => return */
+
+	shrl $16, %eax		/* make upper bytes accessible */
+	movb %al, 2(%ecx,%edx)	/* store third byte of last word */
+	orb %al, %al		/* is it NUL? */
+	jz L8			/* yes => return */
+
+	movb %ah, 3(%ecx,%edx)	/* store fourth byte of last word */
+
+L8:	movl 8(%esp), %eax	/* start address of destination is result */
+	popl %edi		/* restore saved register */
+
+	ret