[Patch] Replace MIPS strcmp.c with assembly language version.

[Patch] Replace MIPS strcmp.c with assembly language version.

[Steve Ellcey]

I would like to replace the MIPS C strcmp.c with an assembly language
version that is a bit faster.  Both versions load 4 bytes at a time on
aligned strings but the assembly version has the advantage of being
scheduled by hand and having some loop unrolling to be a bit faster.
This version is already checked in to glibc.  It has been tested by
hand and by running the GCC testsuite.

OK for checkin?

Steve Ellcey
sellcey@mips.com


2014-10-02  Steve Ellcey  <sellcey@mips.com>

	* newlib/libc/machine/mips/strcmp.c: Remove.
	* newlib/libc/machine/mips/strcmp.S: New.
	* newlib/libc/machine/mips/Makefile.am (lib_a_SOURCES):
	Replace strcmp.c with strcmp.S
	* newlib/libc/machine/mips/Makefile.in: Regenerate.


diff --git a/newlib/libc/machine/mips/Makefile.am b/newlib/libc/machine/mips/Makefile.am
index 46b4cc3..1695b18 100644
--- a/newlib/libc/machine/mips/Makefile.am
+++ b/newlib/libc/machine/mips/Makefile.am
@@ -8,7 +8,7 @@ AM_CCASFLAGS = $(INCLUDES)
 
 noinst_LIBRARIES = lib.a
 
-lib_a_SOURCES = setjmp.S strlen.c strcmp.c strncpy.c memset.S memcpy.S
+lib_a_SOURCES = setjmp.S strlen.c strcmp.S strncpy.c memset.S memcpy.S
 lib_a_CCASFLAGS=$(AM_CCASFLAGS) -D_COMPILING_NEWLIB
 lib_a_CFLAGS=$(AM_CFLAGS) -D_COMPILING_NEWLIB
 
diff --git a/newlib/libc/machine/mips/strcmp.S b/newlib/libc/machine/mips/strcmp.S
new file mode 100644
index 0000000..b1d757e
--- /dev/null
+++ b/newlib/libc/machine/mips/strcmp.S
@@ -0,0 +1,261 @@
+/*
+ * Copyright (c) 2014
+ *      Imagination Technologies Limited.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the MIPS Technologies, Inc., nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY IMAGINATION TECHNOLOGIES LIMITED ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL IMAGINATION TECHNOLOGIES LIMITED BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifdef ANDROID_CHANGES
+# include "machine/asm.h"
+# include "machine/regdef.h"
+#elif _LIBC
+# include <sysdep.h>
+# include <regdef.h>
+# include <sys/asm.h>
+#elif _COMPILING_NEWLIB
+# include "machine/asm.h"
+# include "machine/regdef.h"
+#else
+# include <regdef.h>
+# include <sys/asm.h>
+#endif
+
+/* Technically strcmp should not read past the end of the strings being
+   compared.  We will read a full word that may contain excess bits beyond
+   the NULL string terminator but unless ENABLE_READAHEAD is set, we will not
+   read the next word after the end of string.  Setting ENABLE_READAHEAD will
+   improve performance but is technically illegal based on the definition of
+   strcmp.  */
+#ifdef ENABLE_READAHEAD
+# define DELAY_READ
+#else
+# define DELAY_READ nop
+#endif
+
+/* Testing on a little endian machine showed using CLZ was a
+   performance loss, so we are not turning it on by default.  */
+#if defined(ENABLE_CLZ) && (__mips_isa_rev > 1)
+# define USE_CLZ
+#endif
+
+/* Some asm.h files do not have the L macro definition.  */
+#ifndef L
+# if _MIPS_SIM == _ABIO32
+#  define L(label) $L ## label
+# else
+#  define L(label) .L ## label
+# endif
+#endif
+
+/* Some asm.h files do not have the PTR_ADDIU macro definition.  */
+#ifndef PTR_ADDIU
+# ifdef USE_DOUBLE
+#  define PTR_ADDIU       daddiu
+# else
+#  define PTR_ADDIU       addiu
+# endif
+#endif
+
+/* Allow the routine to be named something else if desired.  */
+#ifndef STRCMP_NAME
+# define STRCMP_NAME strcmp
+#endif
+
+#ifdef ANDROID_CHANGES
+LEAF(STRCMP_NAME, 0)
+#else
+LEAF(STRCMP_NAME)
+#endif
+	.set	nomips16
+	.set	noreorder
+
+	or	t0, a0, a1
+	andi	t0,0x3
+	bne	t0, zero, L(byteloop)
+
+/* Both strings are 4 byte aligned at this point.  */
+
+	lui	t8, 0x0101
+	ori	t8, t8, 0x0101
+	lui	t9, 0x7f7f
+	ori	t9, 0x7f7f
+
+#define STRCMP32(OFFSET) \
+	lw	v0, OFFSET(a0); \
+	lw	v1, OFFSET(a1); \
+	subu	t0, v0, t8; \
+	bne	v0, v1, L(worddiff); \
+	nor	t1, v0, t9; \
+	and	t0, t0, t1; \
+	bne	t0, zero, L(returnzero)
+
+L(wordloop):
+	STRCMP32(0)
+	DELAY_READ
+	STRCMP32(4)
+	DELAY_READ
+	STRCMP32(8)
+	DELAY_READ
+	STRCMP32(12)
+	DELAY_READ
+	STRCMP32(16)
+	DELAY_READ
+	STRCMP32(20)
+	DELAY_READ
+	STRCMP32(24)
+	DELAY_READ
+	STRCMP32(28)
+	PTR_ADDIU a0, a0, 32
+	b	L(wordloop)
+	PTR_ADDIU a1, a1, 32
+
+L(returnzero):
+	j	ra
+	move	v0, zero
+
+L(worddiff):
+#ifdef USE_CLZ
+	subu	t0, v0, t8
+	nor	t1, v0, t9
+	and	t1, t0, t1
+	xor	t0, v0, v1
+	or	t0, t0, t1
+# if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	wsbh	t0, t0
+	rotr	t0, t0, 16
+# endif
+	clz	t1, t0
+	and	t1, 0xf8
+# if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+	neg	t1
+	addu	t1, 24
+# endif
+	rotrv	v0, v0, t1
+	rotrv	v1, v1, t1
+	and	v0, v0, 0xff
+	and	v1, v1, 0xff
+	j	ra
+	subu	v0, v0, v1
+#else /* USE_CLZ */
+# if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	andi	t0, v0, 0xff
+	beq	t0, zero, L(wexit01)
+	andi	t1, v1, 0xff
+	bne	t0, t1, L(wexit01)
+
+	srl	t8, v0, 8
+	srl	t9, v1, 8
+	andi	t8, t8, 0xff
+	beq	t8, zero, L(wexit89)
+	andi	t9, t9, 0xff
+	bne	t8, t9, L(wexit89)
+
+	srl	t0, v0, 16
+	srl	t1, v1, 16
+	andi	t0, t0, 0xff
+	beq	t0, zero, L(wexit01)
+	andi	t1, t1, 0xff
+	bne	t0, t1, L(wexit01)
+
+	srl	t8, v0, 24
+	srl	t9, v1, 24
+# else /* __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ */
+	srl	t0, v0, 24
+	beq	t0, zero, L(wexit01)
+	srl	t1, v1, 24
+	bne	t0, t1, L(wexit01)
+
+	srl	t8, v0, 16
+	srl	t9, v1, 16
+	andi	t8, t8, 0xff
+	beq	t8, zero, L(wexit89)
+	andi	t9, t9, 0xff
+	bne	t8, t9, L(wexit89)
+
+	srl	t0, v0, 8
+	srl	t1, v1, 8
+	andi	t0, t0, 0xff
+	beq	t0, zero, L(wexit01)
+	andi	t1, t1, 0xff
+	bne	t0, t1, L(wexit01)
+
+	andi	t8, v0, 0xff
+	andi	t9, v1, 0xff
+# endif /* __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ */
+
+L(wexit89):
+	j	ra
+	subu	v0, t8, t9
+L(wexit01):
+	j	ra
+	subu	v0, t0, t1
+#endif /* USE_CLZ */
+
+/* It might seem better to do the 'beq' instruction between the two 'lbu'
+   instructions so that the nop is not needed but testing showed that this
+   code is actually faster (based on glibc strcmp test).  */
+#define BYTECMP01(OFFSET) \
+	lbu	v0, OFFSET(a0); \
+	lbu	v1, OFFSET(a1); \
+	beq	v0, zero, L(bexit01); \
+	nop; \
+	bne	v0, v1, L(bexit01)
+
+#define BYTECMP89(OFFSET) \
+	lbu	t8, OFFSET(a0); \
+	lbu	t9, OFFSET(a1); \
+	beq	t8, zero, L(bexit89); \
+	nop;	\
+	bne	t8, t9, L(bexit89)
+
+L(byteloop):
+	BYTECMP01(0)
+	BYTECMP89(1)
+	BYTECMP01(2)
+	BYTECMP89(3)
+	BYTECMP01(4)
+	BYTECMP89(5)
+	BYTECMP01(6)
+	BYTECMP89(7)
+	PTR_ADDIU a0, a0, 8
+	b	L(byteloop)
+	PTR_ADDIU a1, a1, 8
+
+L(bexit01):
+	j	ra
+	subu	v0, v0, v1
+L(bexit89):
+	j	ra
+	subu	v0, t8, t9
+
+	.set	at
+	.set	reorder
+
+END(STRCMP_NAME)
+#ifndef ANDROID_CHANGES
+# ifdef _LIBC
+libc_hidden_builtin_def (STRCMP_NAME)
+# endif
+#endif

Re: [Patch] Replace MIPS strcmp.c with assembly language version.

[Jeff Johnston]

I noticed that the glibc version has an LGPL license.  Where did you get this version
from with the BSD-style license?

I also assume this is noticeably better
than the much smaller NetBSD version of MIPS strcmp.S I found on the net: 

http://cvsweb.netbsd.org/bsdweb.cgi/src/common/lib/libc/arch/mips/string/strcmp.S?rev=1.2&content-type=text/x-cvsweb-markup&only_with_tag=MAIN

-- Jeff J.

----- Original Message -----
From: "Steve Ellcey" <sellcey@mips.com>
To: newlib@sourceware.org
Cc: c@mips.com
Sent: Thursday, October 2, 2014 4:49:50 PM
Subject: [Patch] Replace MIPS strcmp.c with assembly language version.


I would like to replace the MIPS C strcmp.c with an assembly language
version that is a bit faster.  Both versions load 4 bytes at a time on
aligned strings but the assembly version has the advantage of being
scheduled by hand and having some loop unrolling to be a bit faster.
This version is already checked in to glibc.  It has been tested by
hand and by running the GCC testsuite.

OK for checkin?

Steve Ellcey
sellcey@mips.com


2014-10-02  Steve Ellcey  <sellcey@mips.com>

	* newlib/libc/machine/mips/strcmp.c: Remove.
	* newlib/libc/machine/mips/strcmp.S: New.
	* newlib/libc/machine/mips/Makefile.am (lib_a_SOURCES):
	Replace strcmp.c with strcmp.S
	* newlib/libc/machine/mips/Makefile.in: Regenerate.


diff --git a/newlib/libc/machine/mips/Makefile.am b/newlib/libc/machine/mips/Makefile.am
index 46b4cc3..1695b18 100644
--- a/newlib/libc/machine/mips/Makefile.am
+++ b/newlib/libc/machine/mips/Makefile.am
@@ -8,7 +8,7 @@ AM_CCASFLAGS = $(INCLUDES)
 
 noinst_LIBRARIES = lib.a
 
-lib_a_SOURCES = setjmp.S strlen.c strcmp.c strncpy.c memset.S memcpy.S
+lib_a_SOURCES = setjmp.S strlen.c strcmp.S strncpy.c memset.S memcpy.S
 lib_a_CCASFLAGS=$(AM_CCASFLAGS) -D_COMPILING_NEWLIB
 lib_a_CFLAGS=$(AM_CFLAGS) -D_COMPILING_NEWLIB
 
diff --git a/newlib/libc/machine/mips/strcmp.S b/newlib/libc/machine/mips/strcmp.S
new file mode 100644
index 0000000..b1d757e
--- /dev/null
+++ b/newlib/libc/machine/mips/strcmp.S
@@ -0,0 +1,261 @@
+/*
+ * Copyright (c) 2014
+ *      Imagination Technologies Limited.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the MIPS Technologies, Inc., nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY IMAGINATION TECHNOLOGIES LIMITED ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL IMAGINATION TECHNOLOGIES LIMITED BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifdef ANDROID_CHANGES
+# include "machine/asm.h"
+# include "machine/regdef.h"
+#elif _LIBC
+# include <sysdep.h>
+# include <regdef.h>
+# include <sys/asm.h>
+#elif _COMPILING_NEWLIB
+# include "machine/asm.h"
+# include "machine/regdef.h"
+#else
+# include <regdef.h>
+# include <sys/asm.h>
+#endif
+
+/* Technically strcmp should not read past the end of the strings being
+   compared.  We will read a full word that may contain excess bits beyond
+   the NULL string terminator but unless ENABLE_READAHEAD is set, we will not
+   read the next word after the end of string.  Setting ENABLE_READAHEAD will
+   improve performance but is technically illegal based on the definition of
+   strcmp.  */
+#ifdef ENABLE_READAHEAD
+# define DELAY_READ
+#else
+# define DELAY_READ nop
+#endif
+
+/* Testing on a little endian machine showed using CLZ was a
+   performance loss, so we are not turning it on by default.  */
+#if defined(ENABLE_CLZ) && (__mips_isa_rev > 1)
+# define USE_CLZ
+#endif
+
+/* Some asm.h files do not have the L macro definition.  */
+#ifndef L
+# if _MIPS_SIM == _ABIO32
+#  define L(label) $L ## label
+# else
+#  define L(label) .L ## label
+# endif
+#endif
+
+/* Some asm.h files do not have the PTR_ADDIU macro definition.  */
+#ifndef PTR_ADDIU
+# ifdef USE_DOUBLE
+#  define PTR_ADDIU       daddiu
+# else
+#  define PTR_ADDIU       addiu
+# endif
+#endif
+
+/* Allow the routine to be named something else if desired.  */
+#ifndef STRCMP_NAME
+# define STRCMP_NAME strcmp
+#endif
+
+#ifdef ANDROID_CHANGES
+LEAF(STRCMP_NAME, 0)
+#else
+LEAF(STRCMP_NAME)
+#endif
+	.set	nomips16
+	.set	noreorder
+
+	or	t0, a0, a1
+	andi	t0,0x3
+	bne	t0, zero, L(byteloop)
+
+/* Both strings are 4 byte aligned at this point.  */
+
+	lui	t8, 0x0101
+	ori	t8, t8, 0x0101
+	lui	t9, 0x7f7f
+	ori	t9, 0x7f7f
+
+#define STRCMP32(OFFSET) \
+	lw	v0, OFFSET(a0); \
+	lw	v1, OFFSET(a1); \
+	subu	t0, v0, t8; \
+	bne	v0, v1, L(worddiff); \
+	nor	t1, v0, t9; \
+	and	t0, t0, t1; \
+	bne	t0, zero, L(returnzero)
+
+L(wordloop):
+	STRCMP32(0)
+	DELAY_READ
+	STRCMP32(4)
+	DELAY_READ
+	STRCMP32(8)
+	DELAY_READ
+	STRCMP32(12)
+	DELAY_READ
+	STRCMP32(16)
+	DELAY_READ
+	STRCMP32(20)
+	DELAY_READ
+	STRCMP32(24)
+	DELAY_READ
+	STRCMP32(28)
+	PTR_ADDIU a0, a0, 32
+	b	L(wordloop)
+	PTR_ADDIU a1, a1, 32
+
+L(returnzero):
+	j	ra
+	move	v0, zero
+
+L(worddiff):
+#ifdef USE_CLZ
+	subu	t0, v0, t8
+	nor	t1, v0, t9
+	and	t1, t0, t1
+	xor	t0, v0, v1
+	or	t0, t0, t1
+# if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	wsbh	t0, t0
+	rotr	t0, t0, 16
+# endif
+	clz	t1, t0
+	and	t1, 0xf8
+# if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+	neg	t1
+	addu	t1, 24
+# endif
+	rotrv	v0, v0, t1
+	rotrv	v1, v1, t1
+	and	v0, v0, 0xff
+	and	v1, v1, 0xff
+	j	ra
+	subu	v0, v0, v1
+#else /* USE_CLZ */
+# if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+	andi	t0, v0, 0xff
+	beq	t0, zero, L(wexit01)
+	andi	t1, v1, 0xff
+	bne	t0, t1, L(wexit01)
+
+	srl	t8, v0, 8
+	srl	t9, v1, 8
+	andi	t8, t8, 0xff
+	beq	t8, zero, L(wexit89)
+	andi	t9, t9, 0xff
+	bne	t8, t9, L(wexit89)
+
+	srl	t0, v0, 16
+	srl	t1, v1, 16
+	andi	t0, t0, 0xff
+	beq	t0, zero, L(wexit01)
+	andi	t1, t1, 0xff
+	bne	t0, t1, L(wexit01)
+
+	srl	t8, v0, 24
+	srl	t9, v1, 24
+# else /* __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ */
+	srl	t0, v0, 24
+	beq	t0, zero, L(wexit01)
+	srl	t1, v1, 24
+	bne	t0, t1, L(wexit01)
+
+	srl	t8, v0, 16
+	srl	t9, v1, 16
+	andi	t8, t8, 0xff
+	beq	t8, zero, L(wexit89)
+	andi	t9, t9, 0xff
+	bne	t8, t9, L(wexit89)
+
+	srl	t0, v0, 8
+	srl	t1, v1, 8
+	andi	t0, t0, 0xff
+	beq	t0, zero, L(wexit01)
+	andi	t1, t1, 0xff
+	bne	t0, t1, L(wexit01)
+
+	andi	t8, v0, 0xff
+	andi	t9, v1, 0xff
+# endif /* __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ */
+
+L(wexit89):
+	j	ra
+	subu	v0, t8, t9
+L(wexit01):
+	j	ra
+	subu	v0, t0, t1
+#endif /* USE_CLZ */
+
+/* It might seem better to do the 'beq' instruction between the two 'lbu'
+   instructions so that the nop is not needed but testing showed that this
+   code is actually faster (based on glibc strcmp test).  */
+#define BYTECMP01(OFFSET) \
+	lbu	v0, OFFSET(a0); \
+	lbu	v1, OFFSET(a1); \
+	beq	v0, zero, L(bexit01); \
+	nop; \
+	bne	v0, v1, L(bexit01)
+
+#define BYTECMP89(OFFSET) \
+	lbu	t8, OFFSET(a0); \
+	lbu	t9, OFFSET(a1); \
+	beq	t8, zero, L(bexit89); \
+	nop;	\
+	bne	t8, t9, L(bexit89)
+
+L(byteloop):
+	BYTECMP01(0)
+	BYTECMP89(1)
+	BYTECMP01(2)
+	BYTECMP89(3)
+	BYTECMP01(4)
+	BYTECMP89(5)
+	BYTECMP01(6)
+	BYTECMP89(7)
+	PTR_ADDIU a0, a0, 8
+	b	L(byteloop)
+	PTR_ADDIU a1, a1, 8
+
+L(bexit01):
+	j	ra
+	subu	v0, v0, v1
+L(bexit89):
+	j	ra
+	subu	v0, t8, t9
+
+	.set	at
+	.set	reorder
+
+END(STRCMP_NAME)
+#ifndef ANDROID_CHANGES
+# ifdef _LIBC
+libc_hidden_builtin_def (STRCMP_NAME)
+# endif
+#endif

Re: [Patch] Replace MIPS strcmp.c with assembly language version.

[Steve Ellcey]

On Wed, 2014-10-08 at 17:36 -0400, Jeff Johnston wrote:
> I noticed that the glibc version has an LGPL license.  Where did you get this version
> from with the BSD-style license?
> 
> I also assume this is noticeably better
> than the much smaller NetBSD version of MIPS strcmp.S I found on the net: 
> 
> http://cvsweb.netbsd.org/bsdweb.cgi/src/common/lib/libc/arch/mips/string/strcmp.S?rev=1.2&content-type=text/x-cvsweb-markup&only_with_tag=MAIN
> 
> -- Jeff J.

I wrote this version of strcmp for glibc and newlib from scratch.  Well,
I did reuse some of my own setup code from memcpy, which is already
checked in to glibc and newlib.

I submitted it to glibc with the LGPL license and to newlib with the
BSD-style license as that is the type of license each project wants, or
at least that was what was requested when I did the new memcpy for MIPS.

Since it was written by me and owned by Imagination, my employer, I
assume there is no problem with me releasing it under multiple licenses
to the different projects.  The copyright assignment from Imagination is
on file with the FSF for both glibc and newlib.

Steve Ellcey

Re: [Patch] Replace MIPS strcmp.c with assembly language version.

[Jeff Johnston]

----- Original Message -----
> From: "Steve Ellcey" <sellcey@mips.com>
> To: "Jeff Johnston" <jjohnstn@redhat.com>
> Cc: newlib@sourceware.org, c@mips.com
> Sent: Wednesday, October 8, 2014 5:54:21 PM
> Subject: Re: [Patch] Replace MIPS strcmp.c with assembly language version.
> 
> On Wed, 2014-10-08 at 17:36 -0400, Jeff Johnston wrote:
> > I noticed that the glibc version has an LGPL license.  Where did you get
> > this version
> > from with the BSD-style license?
> > 
> > I also assume this is noticeably better
> > than the much smaller NetBSD version of MIPS strcmp.S I found on the net:
> > 
> > http://cvsweb.netbsd.org/bsdweb.cgi/src/common/lib/libc/arch/mips/string/strcmp.S?rev=1.2&content-type=text/x-cvsweb-markup&only_with_tag=MAIN
> > 
> > -- Jeff J.
> 
> I wrote this version of strcmp for glibc and newlib from scratch.  Well,
> I did reuse some of my own setup code from memcpy, which is already
> checked in to glibc and newlib.
> 
> I submitted it to glibc with the LGPL license and to newlib with the
> BSD-style license as that is the type of license each project wants, or
> at least that was what was requested when I did the new memcpy for MIPS.
> 

Yes, that is correct.

> Since it was written by me and owned by Imagination, my employer, I
> assume there is no problem with me releasing it under multiple licenses
> to the different projects.  The copyright assignment from Imagination is
> on file with the FSF for both glibc and newlib.

Thanks for clarifying.  Yes, since you wrote the code, that's perfectly ok.
I'm fine with committing the change.

> 
> Steve Ellcey
> 
>