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
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+/* 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)