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.

1 files changed, 334 insertions, 0 deletions

diff --git a/sysdeps/i386/i586/strchr.S b/sysdeps/i386/i586/strchr.S
new file mode 100644
index 0000000000..982c80ec9a
--- /dev/null
+++ b/sysdeps/i386/i586/strchr.S
@@ -0,0 +1,334 @@
+/* strchr -- find character CH in a NUL terminated string.
+Highly optimized version for ix85, x>=5.
+Copyright (C) 1995 Free Software Foundation, Inc.
+This file is part of the GNU C Library.
+Contributed by Ulrich Drepper, <drepper@gnu.ai.mit.edu>.
+
+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>
+
+/* This version is especially optimized for the i586 (and following?)
+   processors.  This is mainly done by using the two pipelines.  The
+   version optimized for i486 is weak in this aspect because to get
+   as much parallelism we have to executs some *more* instructions.
+
+   The code below is structured to reflect the pairing of the instructions
+   as *I think* it is.  I have no processor data book to verify this.
+   If you find something you think is incorrect let me know.  */
+
+
+/* The magic value which is used throughout in the whole code.  */
+#define magic 0xfefefeff
+
+/*
+   INPUT PARAMETERS:
+   str		(sp + 4)
+   ch		(sp + 8)
+*/
+
+	.text
+ENTRY (strchr)
+	pushl %edi		/* Save callee-safe registers.  */
+	pushl %esi
+
+	pushl %ebx
+	pushl %ebp
+
+	movl 20(%esp), %eax	/* get string pointer */
+	movl 24(%esp), %edx	/* get character we are looking for */
+
+	movl %eax, %edi		/* duplicate string pointer for later */
+	xorl %ecx, %ecx		/* clear %ecx */
+
+	/* At the moment %edx contains C.  What we need for the
+	   algorithm is C in all bytes of the dword.  Avoid
+	   operations on 16 bit words because these require an
+	   prefix byte (and one more cycle).  */
+	movb %dl, %dh		/* now it is 0|0|c|c */
+	movb %dl, %cl		/* we construct the lower half in %ecx */
+
+	shll $16, %edx		/* now %edx is c|c|0|0 */
+	movb %cl, %ch		/* now %ecx is 0|0|c|c */
+
+	orl %ecx, %edx		/* and finally c|c|c|c */
+	andl $3, %edi		/* mask alignment bits */
+
+	jz L11			/* alignment is 0 => start loop */
+
+	movb (%eax), %cl	/* load single byte */
+	cmpb %cl, %dl		/* is byte == C? */
+
+	je L2			/* aligned => return pointer */
+
+	cmp $0, %cl		/* is byte NUL? */
+	je L3			/* yes => return NULL */
+
+	incl %eax		/* increment pointer */
+	cmp $3, %edi		/* was alignment == 3? */
+
+	je L11			/* yes => start loop */
+
+	movb (%eax), %cl	/* load single byte */
+	cmpb %cl, %dl		/* is byte == C? */
+
+	je L2			/* aligned => return pointer */
+
+	cmp $0, %cl		/* is byte NUL? */
+	je L3			/* yes => return NULL */
+
+	incl %eax		/* increment pointer */
+	cmp $2, %edi		/* was alignment == 2? */
+
+	je L11			/* yes => start loop */
+
+	movb (%eax), %cl	/* load single byte */
+	cmpb %cl, %dl		/* is byte == C? */
+
+	je L2			/* aligned => return pointer */
+
+	cmp $0, %cl		/* is byte NUL? */
+	je L3			/* yes => return NULL */
+
+	incl %eax		/* increment pointer */
+
+	/* The following code is the preparation for the loop.  The
+	   four instruction up to `L1' will not be executed in the loop
+	   because the same code is found at the end of the loop, but
+	   there it is executed in parallel with other instructions.  */
+L11:	movl (%eax), %ecx
+	movl $magic, %ebp
+
+	movl $magic, %edi
+	addl %ecx, %ebp
+
+	/* The main loop: it looks complex and indeed it is.  I would
+	   love to say `it was hard to write, so it should he hard to
+	   read' but I will give some more hints.  To fully understand
+	   this code you should first take a look at the i486 version.
+	   The basic algorithm is the same, but here the code organized
+	   in a way which permits to use both pipelines all the time.
+
+	   I tried to make it a bit more understandable by indenting
+	   the code according to stage in the algorithm.  It goes as
+	   follows:
+		check for 0 in 1st word
+			check for C in 1st word
+					check for 0 in 2nd word
+						check for C in 2nd word
+		check for 0 in 3rd word
+			check for C in 3rd word
+					check for 0 in 4th word
+						check for C in 4th word
+
+	   Please note that doing the test for NUL before the test for
+	   C allows us to overlap the test for 0 in the next word with
+	   the test for C.  */
+
+L1:	xorl %ecx, %ebp			/* (word^magic) */
+	addl %ecx, %edi			/* add magic word */
+
+	leal 4(%eax), %eax		/* increment pointer */
+	jnc L4				/* previous addl caused overflow? */
+
+		movl %ecx, %ebx		/* duplicate original word */
+	orl $magic, %ebp		/* (word^magic)|magic */
+
+	addl $1, %ebp			/* (word^magic)|magic == 0xffffffff? */
+	jne L4				/* yes => we found word with NUL */
+
+		movl $magic, %esi	/* load magic value */
+		xorl %edx, %ebx		/* clear words which are C */
+
+					movl (%eax), %ecx
+		addl %ebx, %esi		/* (word+magic) */
+
+					movl $magic, %edi
+		jnc L5			/* previous addl caused overflow? */
+
+					movl %edi, %ebp
+		xorl %ebx, %esi		/* (word+magic)^word */
+
+					addl %ecx, %ebp
+		orl $magic, %esi	/* ((word+magic)^word)|magic */
+
+		addl $1, %esi		/* ((word+magic)^word)|magic==0xf..f?*/
+		jne L5			/* yes => we found word with C */
+
+					xorl %ecx, %ebp
+					addl %ecx, %edi
+
+					leal 4(%eax), %eax
+					jnc L4
+
+						movl %ecx, %ebx
+					orl $magic, %ebp
+
+					addl $1, %ebp
+					jne L4
+
+						movl $magic, %esi
+						xorl %edx, %ebx
+
+	movl (%eax), %ecx
+						addl %ebx, %esi
+
+	movl $magic, %edi
+						jnc L5
+
+	movl %edi, %ebp
+						xorl %ebx, %esi
+
+	addl %ecx, %ebp
+						orl $magic, %esi
+
+						addl $1, %esi
+						jne L5
+
+	xorl %ecx, %ebp
+	addl %ecx, %edi
+
+	leal 4(%eax), %eax
+	jnc L4
+
+		movl %ecx, %ebx
+	orl $magic, %ebp
+
+	addl $1, %ebp
+	jne L4
+
+		movl $magic, %esi
+		xorl %edx, %ebx
+
+					movl (%eax), %ecx
+		addl %ebx, %esi
+
+					movl $magic, %edi
+		jnc L5
+
+					movl %edi, %ebp
+		xorl %ebx, %esi
+
+					addl %ecx, %ebp
+		orl $magic, %esi
+
+		addl $1, %esi
+		jne L5
+
+					xorl %ecx, %ebp
+					addl %ecx, %edi
+
+					leal 4(%eax), %eax
+					jnc L4
+
+						movl %ecx, %ebx
+					orl $magic, %ebp
+
+					addl $1, %ebp
+					jne L4
+
+						movl $magic, %esi
+						xorl %edx, %ebx
+
+	movl (%eax), %ecx
+						addl %ebx, %esi
+
+	movl $magic, %edi
+						jnc L5
+
+	movl %edi, %ebp
+						xorl %ebx, %esi
+
+	addl %ecx, %ebp
+						orl $magic, %esi
+
+						addl $1, %esi
+
+						je L1
+
+	/* We know there is no NUL byte but a C byte in the word.
+	   %ebx contains NUL in this particular byte.  */
+L5:	subl $4, %eax		/* adjust pointer */
+	testb %bl, %bl		/* first byte == C? */
+
+	jz L2			/* yes => return pointer */
+
+	incl %eax		/* increment pointer */
+	testb %bh, %bh		/* second byte == C? */
+
+	jz L2			/* yes => return pointer */
+
+	shrl $16, %ebx		/* make upper bytes accessible */
+	incl %eax		/* increment pointer */
+
+	cmp $0, %bl		/* third byte == C */
+	je L2			/* yes => return pointer */
+
+	incl %eax		/* increment pointer */
+
+L2:	popl %ebp		/* restore saved registers */
+	popl %ebx
+
+	popl %esi
+	popl %edi
+
+	ret
+
+	/* We know there is a NUL byte in the word.  But we have to test
+	   whether there is an C byte before it in the word.  */
+L4:	subl $4, %eax		/* adjust pointer */
+	cmpb %dl, %cl		/* first byte == C? */
+
+	je L2			/* yes => return pointer */
+
+	cmpb $0, %cl		/* first byte == NUL? */
+	je L3			/* yes => return NULL */
+
+	incl %eax		/* increment pointer */
+
+	cmpb %dl, %ch		/* second byte == C? */
+	je L2			/* yes => return pointer */
+
+	cmpb $0, %ch		/* second byte == NUL? */
+	je L3			/* yes => return NULL */
+
+	shrl $16, %ecx		/* make upper bytes accessible */
+	incl %eax		/* increment pointer */
+
+	cmpb %dl, %cl		/* third byte == C? */
+	je L2			/* yes => return pointer */
+
+	cmpb $0, %cl		/* third byte == NUL? */
+	je L3			/* yes => return NULL */
+
+	incl %eax		/* increment pointer */
+
+	/* The test four the fourth byte is necessary!  */
+	cmpb %dl, %ch		/* fourth byte == C? */
+	je L2			/* yes => return pointer */
+
+L3:	xorl %eax, %eax		/* set return value = NULL */
+
+	popl %ebp		/* restore saved registers */
+	popl %ebx
+
+	popl %esi
+	popl %edi
+
+	ret
+
+#undef index
+weak_alias (strchr, index)