about summary refs log tree commit diff
path: root/sysdeps/powerpc/strcpy.S
diff options
context:
space:
mode:
Diffstat (limited to 'sysdeps/powerpc/strcpy.S')
-rw-r--r--sysdeps/powerpc/strcpy.S100
1 files changed, 100 insertions, 0 deletions
diff --git a/sysdeps/powerpc/strcpy.S b/sysdeps/powerpc/strcpy.S
new file mode 100644
index 0000000000..3c0cce7844
--- /dev/null
+++ b/sysdeps/powerpc/strcpy.S
@@ -0,0 +1,100 @@
+/* Optimized strcpy implementation for PowerPC.
+   Copyright (C) 1997 Free Software Foundation, Inc.
+   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>
+
+/* See strlen.s for comments on how the end-of-string testing works.  */
+
+EALIGN(strcpy,4,0)
+/* char * [r3] strcpy (char *dest [r3], const char *src [r4])  */
+
+/* General register assignments:
+   r0:	temporary
+   r3:	saved `dest'
+   r4:	pointer to previous word in src
+   r5:	pointer to previous word in dest
+   r6:	current word from src
+   r7:	0xfefefeff
+   r8:	0x7f7f7f7f
+   r9:	~(word in src | 0x7f7f7f7f)
+   r10:	alternate word from src.  */
+
+	or    %r0,%r4,%r3
+	clrlwi. %r0,%r0,30
+	addi  %r5,%r3,-4
+	bne   L(unaligned)
+
+	lis   %r7,0xfeff
+	lis   %r8,0x7f7f
+	lwz   %r6,0(%r4)
+	addi  %r7,%r7,-0x101
+	addi  %r8,%r8,0x7f7f
+	b     2f
+
+0:	lwzu  %r10,4(%r4)
+	stwu  %r6,4(%r5)
+	add   %r0,%r7,%r10
+	nor   %r9,%r8,%r10
+	and.  %r0,%r0,%r9
+	bne-  1f
+	lwzu  %r6,4(%r4)
+	stwu  %r10,4(%r5)
+2:	add   %r0,%r7,%r6
+	nor   %r9,%r8,%r6
+	and.  %r0,%r0,%r9
+	beq+  0b
+
+	mr    %r10,%r6
+/* We've hit the end of the string.  Do the rest byte-by-byte.  */
+1:	rlwinm. %r0,%r10,8,24,31
+	stb   %r0,4(%r5)
+	beqlr-
+	rlwinm. %r0,%r10,16,24,31
+	stb   %r0,5(%r5)
+	beqlr-
+	rlwinm. %r0,%r10,24,24,31
+	stb   %r0,6(%r5)
+	beqlr-
+	stb   %r10,7(%r5)
+	blr
+
+/* Oh well.  In this case, we just do a byte-by-byte copy.  */
+	.align 4
+	nop
+L(unaligned):
+	lbz   %r6,0(%r4)
+	addi  %r5,%r3,-1
+	cmpwi %r6,0
+	beq-  2f
+
+0:	lbzu  %r10,1(%r4)
+	stbu  %r6,1(%r5)
+	cmpwi %r10,0
+	beq-  1f
+	nop		/* Let 601 load start of loop.  */
+	lbzu  %r6,1(%r4)
+	stbu  %r10,1(%r5)
+	cmpwi %r6,0
+	bne+  0b
+2:	stb   %r6,1(%r5)
+	blr
+1:	stb   %r10,1(%r5)
+	blr
+
+END(strcpy)