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, 185 insertions, 0 deletions

diff --git a/sysdeps/i386/i586/strlen.S b/sysdeps/i386/i586/strlen.S
new file mode 100644
index 0000000000..b807ed4b4f
--- /dev/null
+++ b/sysdeps/i386/i586/strlen.S
@@ -0,0 +1,185 @@
+/* strlen -- Compute length og NUL terminated string.
+Highly optimized version for ix86, 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)
+*/
+
+	.text
+ENTRY(strlen)
+	movl 4(%esp), %eax	/* get string pointer */
+
+	movl %eax, %ecx		/* duplicate it */
+	andl $3, %ecx		/* mask alignment bits */
+
+	jz L11			/* aligned => start loop */
+
+	cmpb %ch, (%eax)	/* is byte NUL? */
+	je L2			/* yes => return */
+
+	incl %eax		/* increment pointer */
+	cmpl $3, %ecx		/* was alignment = 3? */
+
+	je L11			/* yes => now it is aligned and start loop */
+
+	cmpb %ch, (%eax)	/* is byte NUL? */
+	je L2			/* yes => return */
+
+	incl %eax		/* increment pointer */
+	cmpl $2, %ecx		/* was alignment = 2? */
+
+	je L11			/* yes => now it is aligned and start loop */
+
+	cmpb %ch, (%eax)	/* is byte NUL? */
+	je L2			/* yes => return */
+
+	incl %eax		/* increment pointer */
+
+      /* We exit the loop if adding MAGIC_BITS to LONGWORD fails to
+	 change any of the hole bits of LONGWORD.
+
+	 1) Is this safe?  Will it catch all the zero bytes?
+	 Suppose there is a byte with all zeros.  Any carry bits
+	 propagating from its left will fall into the hole at its
+	 least significant bit and stop.  Since there will be no
+	 carry from its most significant bit, the LSB of the
+	 byte to the left will be unchanged, and the zero will be
+	 detected.
+
+	 2) Is this worthwhile?  Will it ignore everything except
+	 zero bytes?  Suppose every byte of LONGWORD has a bit set
+	 somewhere.  There will be a carry into bit 8.	If bit 8
+	 is set, this will carry into bit 16.  If bit 8 is clear,
+	 one of bits 9-15 must be set, so there will be a carry
+	 into bit 16.  Similarly, there will be a carry into bit
+	 24.  If one of bits 24-31 is set, there will be a carry
+	 into bit 32 (=carry flag), so all of the hole bits will
+	 be changed.  */
+L11:	xorl %edx, %edx		/* We need %edx == 0 for later */
+
+L1:
+	movl (%eax), %ecx	/* get word (= 4 bytes) in question */
+	addl $4, %eax		/* adjust pointer for *next* word */
+
+	subl %ecx, %edx		/* first step to negate word */
+	addl $magic, %ecx	/* add magic word */
+
+	decl %edx		/* complete negation of word */
+	jnc L3			/* previous addl caused overflow? */
+
+	xorl %ecx, %edx		/* (word+magic)^word */
+	subl $magic, %ecx	/* undo previous addl to restore word */
+
+	andl $~magic, %edx	/* any of the carry flags set? */
+
+	jne L3			/* yes => determine byte */
+
+
+	movl (%eax), %ecx	/* get word (= 4 bytes) in question */
+	addl $4, %eax		/* adjust pointer for *next* word */
+
+	subl %ecx, %edx		/* first step to negate word */
+	addl $magic, %ecx	/* add magic word */
+
+	decl %edx		/* complete negation of word */
+	jnc L3			/* previous addl caused overflow? */
+
+	xorl %ecx, %edx		/* (word+magic)^word */
+	subl $magic, %ecx	/* undo previous addl to restore word */
+
+	andl $~magic, %edx	/* any of the carry flags set? */
+
+	jne L3			/* yes => determine byte */
+
+
+	movl (%eax), %ecx	/* get word (= 4 bytes) in question */
+	addl $4, %eax		/* adjust pointer for *next* word */
+
+	subl %ecx, %edx		/* first step to negate word */
+	addl $magic, %ecx	/* add magic word */
+
+	decl %edx		/* complete negation of word */
+	jnc L3			/* previous addl caused overflow? */
+
+	xorl %ecx, %edx		/* (word+magic)^word */
+	subl $magic, %ecx	/* undo previous addl to restore word */
+
+	andl $~magic, %edx	/* any of the carry flags set? */
+
+	jne L3			/* yes => determine byte */
+
+
+	movl (%eax), %ecx	/* get word (= 4 bytes) in question */
+	addl $4, %eax		/* adjust pointer for *next* word */
+
+	subl %ecx, %edx		/* first step to negate word */
+	addl $magic, %ecx	/* add magic word */
+
+	decl %edx		/* wcomplete negation of ord */
+	jnc L3			/* previous addl caused overflow? */
+
+	xorl %ecx, %edx		/* (word+magic)^word */
+	subl $magic, %ecx	/* undo previous addl to restore word */
+
+	andl $~magic, %edx	/* any of the carry flags set? */
+
+	je L1			/* no => start loop again */
+
+
+L3:	subl $4, %eax		/* correct too early pointer increment */
+	testb %cl, %cl		/* lowest byte NUL? */
+
+	jz L2			/* yes => return */
+
+	inc %eax		/* increment pointer */
+	testb %ch, %ch		/* second byte NUL? */
+
+	jz L2			/* yes => return */
+
+	shrl $16, %ecx		/* make upper bytes accessible */
+	incl %eax		/* increment pointer */
+
+	cmpb $0, %cl		/* is third byte NUL? */
+	jz L2			/* yes => return */
+
+	incl %eax		/* increment pointer */
+
+L2:	subl 4(%esp), %eax	/* now compute the length as difference
+				   between start and terminating NUL
+				   character */
+
+	ret