diff mbox

[v3] ARM: Add Cortex-A15 optimized NEON and VFP memcpy routines, with IFUNC.

Message ID 51752F94.8080105@linaro.org
State Superseded
Headers show

Commit Message

Will Newton April 22, 2013, 12:39 p.m. UTC
Add a high performance memcpy routine optimized for Cortex-A15 with
variants for use in the presence of NEON and VFP hardware selected
at runtime using indirect function support.

This was tested on armv7l-unknown-linux-gnueabihf. One new testsuite
failure was introduced (elf/ifuncmain5picstatic) which was caused by
a bug in ld. A fix for that ld issue has been submitted here:

  http://sourceware.org/ml/binutils/2013-04/msg00143.html

ports/ChangeLog.arm:

2013-04-15  Will Newton  <will.newton@linaro.org>

	* sysdeps/arm/armv7/multiarch/Makefile: New file.
	* sysdeps/arm/armv7/multiarch/aeabi_memcpy.c: Likewise.
	* sysdeps/arm/armv7/multiarch/ifunc-impl-list.c: Likewise.
	* sysdeps/arm/armv7/multiarch/memcpy.S: Likewise.
	* sysdeps/arm/armv7/multiarch/memcpy_impl.S: Likewise.
	* sysdeps/arm/armv7/multiarch/memcpy_neon.S: Likewise.
	* sysdeps/arm/armv7/multiarch/memcpy_vfp.S: Likewise.
---
 ports/sysdeps/arm/armv7/multiarch/Makefile         |   3 +
 ports/sysdeps/arm/armv7/multiarch/aeabi_memcpy.c   |  33 ++
 .../sysdeps/arm/armv7/multiarch/ifunc-impl-list.c  |  46 ++
 ports/sysdeps/arm/armv7/multiarch/memcpy.S         |  60 ++
 ports/sysdeps/arm/armv7/multiarch/memcpy_impl.S    | 602 +++++++++++++++++++++
 ports/sysdeps/arm/armv7/multiarch/memcpy_neon.S    |   3 +
 ports/sysdeps/arm/armv7/multiarch/memcpy_vfp.S     |   3 +
 7 files changed, 750 insertions(+)
 create mode 100644 ports/sysdeps/arm/armv7/multiarch/Makefile
 create mode 100644 ports/sysdeps/arm/armv7/multiarch/aeabi_memcpy.c
 create mode 100644 ports/sysdeps/arm/armv7/multiarch/ifunc-impl-list.c
 create mode 100644 ports/sysdeps/arm/armv7/multiarch/memcpy.S
 create mode 100644 ports/sysdeps/arm/armv7/multiarch/memcpy_impl.S
 create mode 100644 ports/sysdeps/arm/armv7/multiarch/memcpy_neon.S
 create mode 100644 ports/sysdeps/arm/armv7/multiarch/memcpy_vfp.S

Changes in v3:
 - All memcpy code now ARM rather than Thumb.
 - Simplify indirect function further.
 - Add implementation of __aeabi_mempcy which calls __memcpy_arm.

Comments

Joseph Myers April 26, 2013, 5:05 p.m. UTC | #1
On Mon, 22 Apr 2013, Will Newton wrote:

> diff --git a/ports/sysdeps/arm/armv7/multiarch/ifunc-impl-list.c b/ports/sysdeps/arm/armv7/multiarch/ifunc-impl-list.c

> +#include <assert.h>
> +#include <string.h>
> +#include <wchar.h>
> +#include <ldsodefs.h>
> +#include <sysdep.h>
> +#include <ifunc-impl-list.h>

What's the need for <assert.h> and <wchar.h>?  I don't see anything 
obviously using them in this file.  (If it's an indirect use, it's 
probably better to make the header in question include the other header it 
needs, so each file is including exactly those headers from which it uses 
functionality directly.)

> +	      IFUNC_IMPL_ADD (array, i, memcpy, hwcap & HWCAP_ARM_VFPv3,
> +			      __memcpy_vfp)

Why VFPv3 here?  In the .S file you use HWCAP_ARM_VFP.

> diff --git a/ports/sysdeps/arm/armv7/multiarch/memcpy.S b/ports/sysdeps/arm/armv7/multiarch/memcpy.S

> +#include <arm-features.h>

I don't see any actual use of anything from arm-features.h here.  
(Arguably you *should* be using it - if ARM_HAVE_VFP, you don't need to 
consider the possibility of VFP being missing, although you still need to 
build __memcpy_arm for __aeabi_memcpy use.  And if the compiler has NEON 
enabled for the build, __memcpy_vfp isn't needed at all, although in that 
case it would be better to avoid all the IFUNC handling and just have 
__memcpy_arm for __aeabi_memcpy and use in ld.so.  But in any case, either 
use arm-features.h or remove the include.)

> +/* Old versions of GAS incorrectly implement the NEON align semantics.  */

State explicit version numbers, "versions before x.y".  That way we can 
tell when this code is obsolete because the versions in question aren't 
supported by glibc.

But, since I don't see a configure test that would set this 
BROKEN_ASM_NEON_ALIGN macro, if it's relevant for binutils 2.20 (the 
oldest version supported by glibc at present) then there should be such a 
test, and if it's not relevant for 2.20 then the conditionals shouldn't be 
here at all.  (Or, you could make a case for a more recent binutils 
version as the minimum on ARM, but there should probably be a configure 
test for that if a more recent version is needed.)

> +#define PC_OFFSET	8	/* PC pipeline compensation.  */

We have a macro PC_OFS in sysdep.h, I suggest using it.

> +.Lcpy_not_short:
> +	/* At least 64 bytes to copy, but don't know the alignment yet.  */
> +	str	tmp2, [sp, #-FRAME_SIZE]!

All stack adjustments and saves/restores of call-preserved registers 
should have associated CFI annotations for debug info (you may also need 
cfi_remember_state / cfi_restore_start in appropriate places where 
branches are involved, so that the CFI is correct at all places in the 
function; this is just the first example of a place needing CFI that I 
saw).
Will Newton April 30, 2013, 9:46 a.m. UTC | #2
On 26 April 2013 18:05, Joseph S. Myers <joseph@codesourcery.com> wrote:

Hi Joseph,

Thanks for the further patch review!

>> diff --git a/ports/sysdeps/arm/armv7/multiarch/ifunc-impl-list.c b/ports/sysdeps/arm/armv7/multiarch/ifunc-impl-list.c
>
>> +#include <assert.h>
>> +#include <string.h>
>> +#include <wchar.h>
>> +#include <ldsodefs.h>
>> +#include <sysdep.h>
>> +#include <ifunc-impl-list.h>
>
> What's the need for <assert.h> and <wchar.h>?  I don't see anything
> obviously using them in this file.  (If it's an indirect use, it's
> probably better to make the header in question include the other header it
> needs, so each file is including exactly those headers from which it uses
> functionality directly.)

They aren't used, I've removed them.

>> +           IFUNC_IMPL_ADD (array, i, memcpy, hwcap & HWCAP_ARM_VFPv3,
>> +                           __memcpy_vfp)
>
> Why VFPv3 here?  In the .S file you use HWCAP_ARM_VFP.

Yes, VFP is the correct constant, fixed.

>> diff --git a/ports/sysdeps/arm/armv7/multiarch/memcpy.S b/ports/sysdeps/arm/armv7/multiarch/memcpy.S
>
>> +#include <arm-features.h>
>
> I don't see any actual use of anything from arm-features.h here.
> (Arguably you *should* be using it - if ARM_HAVE_VFP, you don't need to
> consider the possibility of VFP being missing, although you still need to
> build __memcpy_arm for __aeabi_memcpy use.  And if the compiler has NEON
> enabled for the build, __memcpy_vfp isn't needed at all, although in that
> case it would be better to avoid all the IFUNC handling and just have
> __memcpy_arm for __aeabi_memcpy and use in ld.so.  But in any case, either
> use arm-features.h or remove the include.)

I've removed the include.

>> +/* Old versions of GAS incorrectly implement the NEON align semantics.  */
>
> State explicit version numbers, "versions before x.y".  That way we can
> tell when this code is obsolete because the versions in question aren't
> supported by glibc.
>
> But, since I don't see a configure test that would set this
> BROKEN_ASM_NEON_ALIGN macro, if it's relevant for binutils 2.20 (the
> oldest version supported by glibc at present) then there should be such a
> test, and if it's not relevant for 2.20 then the conditionals shouldn't be
> here at all.  (Or, you could make a case for a more recent binutils
> version as the minimum on ARM, but there should probably be a configure
> test for that if a more recent version is needed.)

AFAIK binutils 2.20 and earlier are broken. I've added a configure
test to make sure arm builds with 2.21.

>> +#define PC_OFFSET    8       /* PC pipeline compensation.  */
>
> We have a macro PC_OFS in sysdep.h, I suggest using it.

Done.

>> +.Lcpy_not_short:
>> +     /* At least 64 bytes to copy, but don't know the alignment yet.  */
>> +     str     tmp2, [sp, #-FRAME_SIZE]!
>
> All stack adjustments and saves/restores of call-preserved registers
> should have associated CFI annotations for debug info (you may also need
> cfi_remember_state / cfi_restore_start in appropriate places where
> branches are involved, so that the CFI is correct at all places in the
> function; this is just the first example of a place needing CFI that I
> saw).

I've added CFI annotations which are hopefully correct. I would
appreciate if you could have a look at the next version of the patch
though as I'm not that conversant with CFI.

Thanks!

--
Will Newton
Toolchain Working Group, Linaro
diff mbox

Patch

diff --git a/ports/sysdeps/arm/armv7/multiarch/Makefile b/ports/sysdeps/arm/armv7/multiarch/Makefile
new file mode 100644
index 0000000..e834cc9
--- /dev/null
+++ b/ports/sysdeps/arm/armv7/multiarch/Makefile
@@ -0,0 +1,3 @@ 
+ifeq ($(subdir),string)
+sysdep_routines += memcpy_neon memcpy_vfp
+endif
diff --git a/ports/sysdeps/arm/armv7/multiarch/aeabi_memcpy.c b/ports/sysdeps/arm/armv7/multiarch/aeabi_memcpy.c
new file mode 100644
index 0000000..1f163b3
--- /dev/null
+++ b/ports/sysdeps/arm/armv7/multiarch/aeabi_memcpy.c
@@ -0,0 +1,33 @@ 
+/* Copyright (C) 2005-2013 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 Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <string.h>
+
+void *__memcpy_arm (void *dest, const void *src, size_t n);
+
+/* Copy memory like memcpy, but no return value required.  Can't alias
+   to memcpy because it's not defined in the same translation
+   unit.  */
+void
+__aeabi_memcpy (void *dest, const void *src, size_t n)
+{
+  __memcpy_arm (dest, src, n);
+}
+
+/* Versions of the above which may assume memory alignment.  */
+strong_alias (__aeabi_memcpy, __aeabi_memcpy4)
+strong_alias (__aeabi_memcpy, __aeabi_memcpy8)
diff --git a/ports/sysdeps/arm/armv7/multiarch/ifunc-impl-list.c b/ports/sysdeps/arm/armv7/multiarch/ifunc-impl-list.c
new file mode 100644
index 0000000..176288b
--- /dev/null
+++ b/ports/sysdeps/arm/armv7/multiarch/ifunc-impl-list.c
@@ -0,0 +1,46 @@ 
+/* Enumerate available IFUNC implementations of a function.  arm version.
+   Copyright (C) 2013 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 Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <assert.h>
+#include <string.h>
+#include <wchar.h>
+#include <ldsodefs.h>
+#include <sysdep.h>
+#include <ifunc-impl-list.h>
+
+/* Fill ARRAY of MAX elements with IFUNC implementations for function
+   NAME and return the number of valid entries.  */
+
+size_t
+__libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
+			size_t max)
+{
+  size_t i = 0;
+  int hwcap;
+
+  hwcap = GLRO(dl_hwcap);
+
+  IFUNC_IMPL (i, name, memcpy,
+	      IFUNC_IMPL_ADD (array, i, memcpy, hwcap & HWCAP_ARM_NEON,
+			      __memcpy_neon)
+	      IFUNC_IMPL_ADD (array, i, memcpy, hwcap & HWCAP_ARM_VFPv3,
+			      __memcpy_vfp)
+	      IFUNC_IMPL_ADD (array, i, memcpy, 1, __memcpy_arm));
+
+  return i;
+}
diff --git a/ports/sysdeps/arm/armv7/multiarch/memcpy.S b/ports/sysdeps/arm/armv7/multiarch/memcpy.S
new file mode 100644
index 0000000..d82e9b1
--- /dev/null
+++ b/ports/sysdeps/arm/armv7/multiarch/memcpy.S
@@ -0,0 +1,60 @@ 
+/* Multiple versions of memcpy
+   All versions must be listed in ifunc-impl-list.c.
+   Copyright (C) 2013 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 Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#define NO_THUMB
+#include <sysdep.h>
+#include <rtld-global-offsets.h>
+#include <arm-features.h>
+
+#if !defined NOT_IN_libc
+	.text
+ENTRY(memcpy)
+	.type	memcpy, %gnu_indirect_function
+	ldr	r1, .Lmemcpy_arm
+	tst	r0, #HWCAP_ARM_VFP
+	ldrne	r1, .Lmemcpy_vfp
+	tst	r0, #HWCAP_ARM_NEON
+	ldrne	r1, .Lmemcpy_neon
+1:
+	add	r0, r1, pc
+	DO_RET(lr)
+
+.Lmemcpy_arm:
+	.long	C_SYMBOL_NAME(__memcpy_arm) - 1b - PC_OFS
+.Lmemcpy_neon:
+	.long	C_SYMBOL_NAME(__memcpy_neon) - 1b - PC_OFS
+.Lmemcpy_vfp:
+	.long	C_SYMBOL_NAME(__memcpy_vfp) - 1b - PC_OFS
+
+END(memcpy)
+
+libc_hidden_builtin_def (memcpy)
+
+#undef libc_hidden_builtin_def
+#define libc_hidden_builtin_def(name)
+#undef weak_alias
+#define weak_alias(x, y)
+#undef libc_hidden_def
+#define libc_hidden_def(name)
+
+#define memcpy __memcpy_arm
+
+#endif
+
+#include "memcpy_impl.S"
diff --git a/ports/sysdeps/arm/armv7/multiarch/memcpy_impl.S b/ports/sysdeps/arm/armv7/multiarch/memcpy_impl.S
new file mode 100644
index 0000000..ed061da
--- /dev/null
+++ b/ports/sysdeps/arm/armv7/multiarch/memcpy_impl.S
@@ -0,0 +1,602 @@ 
+/* NEON/VFP/ARM version of memcpy optimized for Cortex-A15.
+   Copyright (C) 2013 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 Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.
+
+   This memcpy routine is optimised for Cortex-A15 cores and takes advantage
+   of VFP or NEON when built with the appropriate flags.
+
+   Assumptions:
+
+    ARMv6 (ARMv7-a if using Neon)
+    ARM state
+    Unaligned accesses
+    LDRD/STRD support unaligned word accesses
+
+ */
+#ifndef NO_THUMB
+#define NO_THUMB
+#endif
+#include <sysdep.h>
+
+	.syntax unified
+	/* This implementation requires ARM state.  */
+	.arm
+
+#ifdef MEMCPY_NEON
+
+	.fpu	neon
+	.arch	armv7-a
+# define FRAME_SIZE	4
+# define USE_VFP
+# define USE_NEON
+
+#elif defined (MEMCPY_VFP)
+
+	.arch	armv6
+	.fpu	vfpv2
+# define FRAME_SIZE	32
+# define USE_VFP
+
+#else
+	.arch	armv6
+# define FRAME_SIZE    32
+
+#endif
+
+/* Old versions of GAS incorrectly implement the NEON align semantics.  */
+#ifdef BROKEN_ASM_NEON_ALIGN
+#define ALIGN(addr, align) addr,:align
+#else
+#define ALIGN(addr, align) addr:align
+#endif
+
+#define PC_OFFSET	8	/* PC pipeline compensation.  */
+#define INSN_SIZE	4
+
+/* Call parameters.  */
+#define dstin	r0
+#define src	r1
+#define count	r2
+
+/* Locals.  */
+#define tmp1	r3
+#define dst	ip
+#define tmp2	r10
+
+#ifndef USE_NEON
+/* For bulk copies using GP registers.  */
+#define	A_l	r2		/* Call-clobbered.  */
+#define	A_h	r3		/* Call-clobbered.  */
+#define	B_l	r4
+#define	B_h	r5
+#define	C_l	r6
+#define	C_h	r7
+#define	D_l	r8
+#define	D_h	r9
+#endif
+
+/* Number of lines ahead to pre-fetch data.  If you change this the code
+   below will need adjustment to compensate.  */
+
+#define prefetch_lines	5
+
+#ifdef USE_VFP
+	.macro	cpy_line_vfp vreg, base
+	vstr	\vreg, [dst, #\base]
+	vldr	\vreg, [src, #\base]
+	vstr	d0, [dst, #\base + 8]
+	vldr	d0, [src, #\base + 8]
+	vstr	d1, [dst, #\base + 16]
+	vldr	d1, [src, #\base + 16]
+	vstr	d2, [dst, #\base + 24]
+	vldr	d2, [src, #\base + 24]
+	vstr	\vreg, [dst, #\base + 32]
+	vldr	\vreg, [src, #\base + prefetch_lines * 64 - 32]
+	vstr	d0, [dst, #\base + 40]
+	vldr	d0, [src, #\base + 40]
+	vstr	d1, [dst, #\base + 48]
+	vldr	d1, [src, #\base + 48]
+	vstr	d2, [dst, #\base + 56]
+	vldr	d2, [src, #\base + 56]
+	.endm
+
+	.macro	cpy_tail_vfp vreg, base
+	vstr	\vreg, [dst, #\base]
+	vldr	\vreg, [src, #\base]
+	vstr	d0, [dst, #\base + 8]
+	vldr	d0, [src, #\base + 8]
+	vstr	d1, [dst, #\base + 16]
+	vldr	d1, [src, #\base + 16]
+	vstr	d2, [dst, #\base + 24]
+	vldr	d2, [src, #\base + 24]
+	vstr	\vreg, [dst, #\base + 32]
+	vstr	d0, [dst, #\base + 40]
+	vldr	d0, [src, #\base + 40]
+	vstr	d1, [dst, #\base + 48]
+	vldr	d1, [src, #\base + 48]
+	vstr	d2, [dst, #\base + 56]
+	vldr	d2, [src, #\base + 56]
+	.endm
+#endif
+
+	.p2align 6
+ENTRY(memcpy)
+
+	mov	dst, dstin	/* Preserve dstin, we need to return it.  */
+	cmp	count, #64
+	bge	.Lcpy_not_short
+	/* Deal with small copies quickly by dropping straight into the
+	   exit block.  */
+
+.Ltail63unaligned:
+#ifdef USE_NEON
+	and	tmp1, count, #0x38
+	rsb	tmp1, tmp1, #(56 - PC_OFFSET + INSN_SIZE)
+	add	pc, pc, tmp1
+	vld1.8	{d0}, [src]!	/* 14 words to go.  */
+	vst1.8	{d0}, [dst]!
+	vld1.8	{d0}, [src]!	/* 12 words to go.  */
+	vst1.8	{d0}, [dst]!
+	vld1.8	{d0}, [src]!	/* 10 words to go.  */
+	vst1.8	{d0}, [dst]!
+	vld1.8	{d0}, [src]!	/* 8 words to go.  */
+	vst1.8	{d0}, [dst]!
+	vld1.8	{d0}, [src]!	/* 6 words to go.  */
+	vst1.8	{d0}, [dst]!
+	vld1.8	{d0}, [src]!	/* 4 words to go.  */
+	vst1.8	{d0}, [dst]!
+	vld1.8	{d0}, [src]!	/* 2 words to go.  */
+	vst1.8	{d0}, [dst]!
+
+	tst	count, #4
+	ldrne	tmp1, [src], #4
+	strne	tmp1, [dst], #4
+#else
+	/* Copy up to 15 full words of data.  May not be aligned.  */
+	/* Cannot use VFP for unaligned data.  */
+	and	tmp1, count, #0x3c
+	add	dst, dst, tmp1
+	add	src, src, tmp1
+	rsb	tmp1, tmp1, #(60 - PC_OFFSET/2 + INSN_SIZE/2)
+	/* Jump directly into the sequence below at the correct offset.  */
+	add	pc, pc, tmp1, lsl #1
+
+	ldr	tmp1, [src, #-60]	/* 15 words to go.  */
+	str	tmp1, [dst, #-60]
+
+	ldr	tmp1, [src, #-56]	/* 14 words to go.  */
+	str	tmp1, [dst, #-56]
+	ldr	tmp1, [src, #-52]
+	str	tmp1, [dst, #-52]
+
+	ldr	tmp1, [src, #-48]	/* 12 words to go.  */
+	str	tmp1, [dst, #-48]
+	ldr	tmp1, [src, #-44]
+	str	tmp1, [dst, #-44]
+
+	ldr	tmp1, [src, #-40]	/* 10 words to go.  */
+	str	tmp1, [dst, #-40]
+	ldr	tmp1, [src, #-36]
+	str	tmp1, [dst, #-36]
+
+	ldr	tmp1, [src, #-32]	/* 8 words to go.  */
+	str	tmp1, [dst, #-32]
+	ldr	tmp1, [src, #-28]
+	str	tmp1, [dst, #-28]
+
+	ldr	tmp1, [src, #-24]	/* 6 words to go.  */
+	str	tmp1, [dst, #-24]
+	ldr	tmp1, [src, #-20]
+	str	tmp1, [dst, #-20]
+
+	ldr	tmp1, [src, #-16]	/* 4 words to go.  */
+	str	tmp1, [dst, #-16]
+	ldr	tmp1, [src, #-12]
+	str	tmp1, [dst, #-12]
+
+	ldr	tmp1, [src, #-8]	/* 2 words to go.  */
+	str	tmp1, [dst, #-8]
+	ldr	tmp1, [src, #-4]
+	str	tmp1, [dst, #-4]
+#endif
+
+	lsls	count, count, #31
+	ldrhcs	tmp1, [src], #2
+	ldrbne	src, [src]		/* Src is dead, use as a scratch.  */
+	strhcs	tmp1, [dst], #2
+	strbne	src, [dst]
+	bx	lr
+
+.Lcpy_not_short:
+	/* At least 64 bytes to copy, but don't know the alignment yet.  */
+	str	tmp2, [sp, #-FRAME_SIZE]!
+	and	tmp2, src, #3
+	and	tmp1, dst, #3
+	cmp	tmp1, tmp2
+	bne	.Lcpy_notaligned
+
+#ifdef USE_VFP
+	/* Magic dust alert!  Force VFP on Cortex-A9.  Experiments show
+	   that the FP pipeline is much better at streaming loads and
+	   stores.  This is outside the critical loop.  */
+	vmov.f32	s0, s0
+#endif
+
+	/* SRC and DST have the same mutual 32-bit alignment, but we may
+	   still need to pre-copy some bytes to get to natural alignment.
+	   We bring DST into full 64-bit alignment.  */
+	lsls	tmp2, dst, #29
+	beq	1f
+	rsbs	tmp2, tmp2, #0
+	sub	count, count, tmp2, lsr #29
+	ldrmi	tmp1, [src], #4
+	strmi	tmp1, [dst], #4
+	lsls	tmp2, tmp2, #2
+	ldrhcs	tmp1, [src], #2
+	ldrbne	tmp2, [src], #1
+	strhcs	tmp1, [dst], #2
+	strbne	tmp2, [dst], #1
+
+1:
+	subs	tmp2, count, #64	/* Use tmp2 for count.  */
+	blt	.Ltail63aligned
+
+	cmp	tmp2, #512
+	bge	.Lcpy_body_long
+
+.Lcpy_body_medium:			/* Count in tmp2.  */
+#ifdef USE_VFP
+1:
+	vldr	d0, [src, #0]
+	subs	tmp2, tmp2, #64
+	vldr	d1, [src, #8]
+	vstr	d0, [dst, #0]
+	vldr	d0, [src, #16]
+	vstr	d1, [dst, #8]
+	vldr	d1, [src, #24]
+	vstr	d0, [dst, #16]
+	vldr	d0, [src, #32]
+	vstr	d1, [dst, #24]
+	vldr	d1, [src, #40]
+	vstr	d0, [dst, #32]
+	vldr	d0, [src, #48]
+	vstr	d1, [dst, #40]
+	vldr	d1, [src, #56]
+	vstr	d0, [dst, #48]
+	add	src, src, #64
+	vstr	d1, [dst, #56]
+	add	dst, dst, #64
+	bge	1b
+	tst	tmp2, #0x3f
+	beq	.Ldone
+
+.Ltail63aligned:			/* Count in tmp2.  */
+	and	tmp1, tmp2, #0x38
+	add	dst, dst, tmp1
+	add	src, src, tmp1
+	rsb	tmp1, tmp1, #(56 - PC_OFFSET + INSN_SIZE)
+	add	pc, pc, tmp1
+
+	vldr	d0, [src, #-56]	/* 14 words to go.  */
+	vstr	d0, [dst, #-56]
+	vldr	d0, [src, #-48]	/* 12 words to go.  */
+	vstr	d0, [dst, #-48]
+	vldr	d0, [src, #-40]	/* 10 words to go.  */
+	vstr	d0, [dst, #-40]
+	vldr	d0, [src, #-32]	/* 8 words to go.  */
+	vstr	d0, [dst, #-32]
+	vldr	d0, [src, #-24]	/* 6 words to go.  */
+	vstr	d0, [dst, #-24]
+	vldr	d0, [src, #-16]	/* 4 words to go.  */
+	vstr	d0, [dst, #-16]
+	vldr	d0, [src, #-8]	/* 2 words to go.  */
+	vstr	d0, [dst, #-8]
+#else
+	sub	src, src, #8
+	sub	dst, dst, #8
+1:
+	ldrd	A_l, A_h, [src, #8]
+	strd	A_l, A_h, [dst, #8]
+	ldrd	A_l, A_h, [src, #16]
+	strd	A_l, A_h, [dst, #16]
+	ldrd	A_l, A_h, [src, #24]
+	strd	A_l, A_h, [dst, #24]
+	ldrd	A_l, A_h, [src, #32]
+	strd	A_l, A_h, [dst, #32]
+	ldrd	A_l, A_h, [src, #40]
+	strd	A_l, A_h, [dst, #40]
+	ldrd	A_l, A_h, [src, #48]
+	strd	A_l, A_h, [dst, #48]
+	ldrd	A_l, A_h, [src, #56]
+	strd	A_l, A_h, [dst, #56]
+	ldrd	A_l, A_h, [src, #64]!
+	strd	A_l, A_h, [dst, #64]!
+	subs	tmp2, tmp2, #64
+	bge	1b
+	tst	tmp2, #0x3f
+	bne	1f
+	ldr	tmp2,[sp], #FRAME_SIZE
+	bx	lr
+1:
+	add	src, src, #8
+	add	dst, dst, #8
+
+.Ltail63aligned:			/* Count in tmp2.  */
+	/* Copy up to 7 d-words of data.  Similar to Ltail63unaligned, but
+	   we know that the src and dest are 32-bit aligned so we can use
+	   LDRD/STRD to improve efficiency.  */
+	/* TMP2 is now negative, but we don't care about that.  The bottom
+	   six bits still tell us how many bytes are left to copy.  */
+
+	and	tmp1, tmp2, #0x38
+	add	dst, dst, tmp1
+	add	src, src, tmp1
+	rsb	tmp1, tmp1, #(56 - PC_OFFSET + INSN_SIZE)
+	add	pc, pc, tmp1
+	ldrd	A_l, A_h, [src, #-56]	/* 14 words to go.  */
+	strd	A_l, A_h, [dst, #-56]
+	ldrd	A_l, A_h, [src, #-48]	/* 12 words to go.  */
+	strd	A_l, A_h, [dst, #-48]
+	ldrd	A_l, A_h, [src, #-40]	/* 10 words to go.  */
+	strd	A_l, A_h, [dst, #-40]
+	ldrd	A_l, A_h, [src, #-32]	/* 8 words to go.  */
+	strd	A_l, A_h, [dst, #-32]
+	ldrd	A_l, A_h, [src, #-24]	/* 6 words to go.  */
+	strd	A_l, A_h, [dst, #-24]
+	ldrd	A_l, A_h, [src, #-16]	/* 4 words to go.  */
+	strd	A_l, A_h, [dst, #-16]
+	ldrd	A_l, A_h, [src, #-8]	/* 2 words to go.  */
+	strd	A_l, A_h, [dst, #-8]
+
+#endif
+	tst	tmp2, #4
+	ldrne	tmp1, [src], #4
+	strne	tmp1, [dst], #4
+	lsls	tmp2, tmp2, #31		/* Count (tmp2) now dead. */
+	ldrhcs	tmp1, [src], #2
+	ldrbne	tmp2, [src]
+	strhcs	tmp1, [dst], #2
+	strbne	tmp2, [dst]
+
+.Ldone:
+	ldr	tmp2, [sp], #FRAME_SIZE
+	bx	lr
+
+.Lcpy_body_long:			/* Count in tmp2.  */
+
+	/* Long copy.  We know that there's at least (prefetch_lines * 64)
+	   bytes to go.  */
+#ifdef USE_VFP
+	/* Don't use PLD.  Instead, read some data in advance of the current
+	   copy position into a register.  This should act like a PLD
+	   operation but we won't have to repeat the transfer.  */
+
+	vldr	d3, [src, #0]
+	vldr	d4, [src, #64]
+	vldr	d5, [src, #128]
+	vldr	d6, [src, #192]
+	vldr	d7, [src, #256]
+
+	vldr	d0, [src, #8]
+	vldr	d1, [src, #16]
+	vldr	d2, [src, #24]
+	add	src, src, #32
+
+	subs	tmp2, tmp2, #prefetch_lines * 64 * 2
+	blt	2f
+1:
+	cpy_line_vfp	d3, 0
+	cpy_line_vfp	d4, 64
+	cpy_line_vfp	d5, 128
+	add	dst, dst, #3 * 64
+	add	src, src, #3 * 64
+	cpy_line_vfp	d6, 0
+	cpy_line_vfp	d7, 64
+	add	dst, dst, #2 * 64
+	add	src, src, #2 * 64
+	subs	tmp2, tmp2, #prefetch_lines * 64
+	bge	1b
+
+2:
+	cpy_tail_vfp	d3, 0
+	cpy_tail_vfp	d4, 64
+	cpy_tail_vfp	d5, 128
+	add	src, src, #3 * 64
+	add	dst, dst, #3 * 64
+	cpy_tail_vfp	d6, 0
+	vstr	d7, [dst, #64]
+	vldr	d7, [src, #64]
+	vstr	d0, [dst, #64 + 8]
+	vldr	d0, [src, #64 + 8]
+	vstr	d1, [dst, #64 + 16]
+	vldr	d1, [src, #64 + 16]
+	vstr	d2, [dst, #64 + 24]
+	vldr	d2, [src, #64 + 24]
+	vstr	d7, [dst, #64 + 32]
+	add	src, src, #96
+	vstr	d0, [dst, #64 + 40]
+	vstr	d1, [dst, #64 + 48]
+	vstr	d2, [dst, #64 + 56]
+	add	dst, dst, #128
+	add	tmp2, tmp2, #prefetch_lines * 64
+	b	.Lcpy_body_medium
+#else
+	/* Long copy.  Use an SMS style loop to maximize the I/O
+	   bandwidth of the core.  We don't have enough spare registers
+	   to synthesise prefetching, so use PLD operations.  */
+	/* Pre-bias src and dst.  */
+	sub	src, src, #8
+	sub	dst, dst, #8
+	pld	[src, #8]
+	pld	[src, #72]
+	subs	tmp2, tmp2, #64
+	pld	[src, #136]
+	ldrd	A_l, A_h, [src, #8]
+	strd	B_l, B_h, [sp, #8]
+	ldrd	B_l, B_h, [src, #16]
+	strd	C_l, C_h, [sp, #16]
+	ldrd	C_l, C_h, [src, #24]
+	strd	D_l, D_h, [sp, #24]
+	pld	[src, #200]
+	ldrd	D_l, D_h, [src, #32]!
+	b	1f
+	.p2align	6
+2:
+	pld	[src, #232]
+	strd	A_l, A_h, [dst, #40]
+	ldrd	A_l, A_h, [src, #40]
+	strd	B_l, B_h, [dst, #48]
+	ldrd	B_l, B_h, [src, #48]
+	strd	C_l, C_h, [dst, #56]
+	ldrd	C_l, C_h, [src, #56]
+	strd	D_l, D_h, [dst, #64]!
+	ldrd	D_l, D_h, [src, #64]!
+	subs	tmp2, tmp2, #64
+1:
+	strd	A_l, A_h, [dst, #8]
+	ldrd	A_l, A_h, [src, #8]
+	strd	B_l, B_h, [dst, #16]
+	ldrd	B_l, B_h, [src, #16]
+	strd	C_l, C_h, [dst, #24]
+	ldrd	C_l, C_h, [src, #24]
+	strd	D_l, D_h, [dst, #32]
+	ldrd	D_l, D_h, [src, #32]
+	bcs	2b
+	/* Save the remaining bytes and restore the callee-saved regs.  */
+	strd	A_l, A_h, [dst, #40]
+	add	src, src, #40
+	strd	B_l, B_h, [dst, #48]
+	ldrd	B_l, B_h, [sp, #8]
+	strd	C_l, C_h, [dst, #56]
+	ldrd	C_l, C_h, [sp, #16]
+	strd	D_l, D_h, [dst, #64]
+	ldrd	D_l, D_h, [sp, #24]
+	add	dst, dst, #72
+	tst	tmp2, #0x3f
+	bne	.Ltail63aligned
+	ldr	tmp2, [sp], #FRAME_SIZE
+	bx	lr
+#endif
+
+.Lcpy_notaligned:
+	pld	[src]
+	pld	[src, #64]
+	/* There's at least 64 bytes to copy, but there is no mutual
+	   alignment.  */
+	/* Bring DST to 64-bit alignment.  */
+	lsls	tmp2, dst, #29
+	pld	[src, #(2 * 64)]
+	beq	1f
+	rsbs	tmp2, tmp2, #0
+	sub	count, count, tmp2, lsr #29
+	ldrmi	tmp1, [src], #4
+	strmi	tmp1, [dst], #4
+	lsls	tmp2, tmp2, #2
+	ldrbne	tmp1, [src], #1
+	ldrhcs	tmp2, [src], #2
+	strbne	tmp1, [dst], #1
+	strhcs	tmp2, [dst], #2
+1:
+	pld	[src, #(3 * 64)]
+	subs	count, count, #64
+	ldrmi	tmp2, [sp], #FRAME_SIZE
+	bmi	.Ltail63unaligned
+	pld	[src, #(4 * 64)]
+
+#ifdef USE_NEON
+	vld1.8	{d0-d3}, [src]!
+	vld1.8	{d4-d7}, [src]!
+	subs	count, count, #64
+	bmi	2f
+1:
+	pld	[src, #(4 * 64)]
+	vst1.8	{d0-d3}, [ALIGN (dst, 64)]!
+	vld1.8	{d0-d3}, [src]!
+	vst1.8	{d4-d7}, [ALIGN (dst, 64)]!
+	vld1.8	{d4-d7}, [src]!
+	subs	count, count, #64
+	bpl	1b
+2:
+	vst1.8	{d0-d3}, [ALIGN (dst, 64)]!
+	vst1.8	{d4-d7}, [ALIGN (dst, 64)]!
+	ands	count, count, #0x3f
+#else
+	/* Use an SMS style loop to maximize the I/O bandwidth.  */
+	sub	src, src, #4
+	sub	dst, dst, #8
+	subs	tmp2, count, #64	/* Use tmp2 for count.  */
+	ldr	A_l, [src, #4]
+	ldr	A_h, [src, #8]
+	strd	B_l, B_h, [sp, #8]
+	ldr	B_l, [src, #12]
+	ldr	B_h, [src, #16]
+	strd	C_l, C_h, [sp, #16]
+	ldr	C_l, [src, #20]
+	ldr	C_h, [src, #24]
+	strd	D_l, D_h, [sp, #24]
+	ldr	D_l, [src, #28]
+	ldr	D_h, [src, #32]!
+	b	1f
+	.p2align	6
+2:
+	pld	[src, #(5 * 64) - (32 - 4)]
+	strd	A_l, A_h, [dst, #40]
+	ldr	A_l, [src, #36]
+	ldr	A_h, [src, #40]
+	strd	B_l, B_h, [dst, #48]
+	ldr	B_l, [src, #44]
+	ldr	B_h, [src, #48]
+	strd	C_l, C_h, [dst, #56]
+	ldr	C_l, [src, #52]
+	ldr	C_h, [src, #56]
+	strd	D_l, D_h, [dst, #64]!
+	ldr	D_l, [src, #60]
+	ldr	D_h, [src, #64]!
+	subs	tmp2, tmp2, #64
+1:
+	strd	A_l, A_h, [dst, #8]
+	ldr	A_l, [src, #4]
+	ldr	A_h, [src, #8]
+	strd	B_l, B_h, [dst, #16]
+	ldr	B_l, [src, #12]
+	ldr	B_h, [src, #16]
+	strd	C_l, C_h, [dst, #24]
+	ldr	C_l, [src, #20]
+	ldr	C_h, [src, #24]
+	strd	D_l, D_h, [dst, #32]
+	ldr	D_l, [src, #28]
+	ldr	D_h, [src, #32]
+	bcs	2b
+
+	/* Save the remaining bytes and restore the callee-saved regs.  */
+	strd	A_l, A_h, [dst, #40]
+	add	src, src, #36
+	strd	B_l, B_h, [dst, #48]
+	ldrd	B_l, B_h, [sp, #8]
+	strd	C_l, C_h, [dst, #56]
+	ldrd	C_l, C_h, [sp, #16]
+	strd	D_l, D_h, [dst, #64]
+	ldrd	D_l, D_h, [sp, #24]
+	add	dst, dst, #72
+	ands	count, tmp2, #0x3f
+#endif
+	ldr	tmp2, [sp], #FRAME_SIZE
+	bne	.Ltail63unaligned
+	bx	lr
+
+END(memcpy)
+libc_hidden_builtin_def (memcpy)
diff --git a/ports/sysdeps/arm/armv7/multiarch/memcpy_neon.S b/ports/sysdeps/arm/armv7/multiarch/memcpy_neon.S
new file mode 100644
index 0000000..c0ef1f8
--- /dev/null
+++ b/ports/sysdeps/arm/armv7/multiarch/memcpy_neon.S
@@ -0,0 +1,3 @@ 
+#define MEMCPY_NEON
+#define memcpy __memcpy_neon
+#include "memcpy_impl.S"
diff --git a/ports/sysdeps/arm/armv7/multiarch/memcpy_vfp.S b/ports/sysdeps/arm/armv7/multiarch/memcpy_vfp.S
new file mode 100644
index 0000000..d21b702
--- /dev/null
+++ b/ports/sysdeps/arm/armv7/multiarch/memcpy_vfp.S
@@ -0,0 +1,3 @@ 
+#define MEMCPY_VFP
+#define memcpy __memcpy_vfp
+#include "memcpy_impl.S"