third_party/lib/cortex-strings/src/aarch64/memmove.S - zircon/ - Git at Google

 /* Copyright (c) 2013, Linaro Limited
    All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are met:
        * Redistributions of source code must retain the above copyright
          notice, this list of conditions and the following disclaimer.
        * 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.
        * Neither the name of the Linaro 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 THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    "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 THE COPYRIGHT
    HOLDER OR CONTRIBUTORS 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. */

 /*
  * Copyright (c) 2015 ARM Ltd
  * All rights reserved.
  *
  * 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. The name of the company may not be used to endorse or promote
  *    products derived from this software without specific prior written
  *    permission.
  *
  * THIS SOFTWARE IS PROVIDED BY ARM LTD ``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 ARM LTD 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.
  */

 /* Assumptions:
  *
  * ARMv8-a, AArch64, unaligned accesses
  */

 	.macro def_fn f p2align=0
 	.text
 	.p2align \p2align
 	.global \f
 	.type \f, %function
 \f:
 	.endm

 /* Parameters and result.  */
 #define dstin	x0
 #define src	x1
 #define count	x2
 #define srcend	x3
 #define dstend	x4
 #define tmp1	x5
 #define A_l	x6
 #define A_h	x7
 #define B_l	x8
 #define B_h	x9
 #define C_l	x10
 #define C_h	x11
 #define D_l	x12
 #define D_h	x13
 #define E_l	count
 #define E_h	tmp1

 /* All memmoves up to 96 bytes are done by memcpy as it supports overlaps.
    Larger backwards copies are also handled by memcpy. The only remaining
    case is forward large copies.  The destination is aligned, and an
    unrolled loop processes 64 bytes per iteration.
 */

 def_fn memmove, 6
 	sub	tmp1, dstin, src
 	cmp	count, 96
 	ccmp	tmp1, count, 2, hi
 	b.hs	memcpy

 	cbz	tmp1, 3f
 	add	dstend, dstin, count
 	add	srcend, src, count

 	/* Align dstend to 16 byte alignment so that we don't cross cache line
 	   boundaries on both loads and stores.	 There are at least 96 bytes
 	   to copy, so copy 16 bytes unaligned and then align.	The loop
 	   copies 64 bytes per iteration and prefetches one iteration ahead.  */

 	and	tmp1, dstend, 15
 	ldp	D_l, D_h, [srcend, -16]
 	sub	srcend, srcend, tmp1
 	sub	count, count, tmp1
 	ldp	A_l, A_h, [srcend, -16]
 	stp	D_l, D_h, [dstend, -16]
 	ldp	B_l, B_h, [srcend, -32]
 	ldp	C_l, C_h, [srcend, -48]
 	ldp	D_l, D_h, [srcend, -64]!
 	sub	dstend, dstend, tmp1
 	subs	count, count, 128
 	b.ls	2f
 	nop
 1:
 	stp	A_l, A_h, [dstend, -16]
 	ldp	A_l, A_h, [srcend, -16]
 	stp	B_l, B_h, [dstend, -32]
 	ldp	B_l, B_h, [srcend, -32]
 	stp	C_l, C_h, [dstend, -48]
 	ldp	C_l, C_h, [srcend, -48]
 	stp	D_l, D_h, [dstend, -64]!
 	ldp	D_l, D_h, [srcend, -64]!
 	subs	count, count, 64
 	b.hi	1b

 	/* Write the last full set of 64 bytes.	 The remainder is at most 64
 	   bytes, so it is safe to always copy 64 bytes from the start even if
 	   there is just 1 byte left.  */
 2:
 	ldp	E_l, E_h, [src, 48]
 	stp	A_l, A_h, [dstend, -16]
 	ldp	A_l, A_h, [src, 32]
 	stp	B_l, B_h, [dstend, -32]
 	ldp	B_l, B_h, [src, 16]
 	stp	C_l, C_h, [dstend, -48]
 	ldp	C_l, C_h, [src]
 	stp	D_l, D_h, [dstend, -64]
 	stp	E_l, E_h, [dstin, 48]
 	stp	A_l, A_h, [dstin, 32]
 	stp	B_l, B_h, [dstin, 16]
 	stp	C_l, C_h, [dstin]
 3:	ret

 	.size	memmove, . - memmove
	/* Copyright (c) 2013, Linaro Limited
	All rights reserved.

	Redistribution and use in source and binary forms, with or without
	modification, are permitted provided that the following conditions are met:
	* Redistributions of source code must retain the above copyright
	notice, this list of conditions and the following disclaimer.
	* 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.
	* Neither the name of the Linaro 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 THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	"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 THE COPYRIGHT
	HOLDER OR CONTRIBUTORS 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. */

	/*
	* Copyright (c) 2015 ARM Ltd
	* All rights reserved.
	*
	* 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. The name of the company may not be used to endorse or promote
	* products derived from this software without specific prior written
	* permission.
	*
	* THIS SOFTWARE IS PROVIDED BY ARM LTD ``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 ARM LTD 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.
	*/

	/* Assumptions:
	*
	* ARMv8-a, AArch64, unaligned accesses
	*/

	.macro def_fn f p2align=0
	.text
	.p2align \p2align
	.global \f
	.type \f, %function
	\f:
	.endm

	/* Parameters and result. */
	#define dstin x0
	#define src x1
	#define count x2
	#define srcend x3
	#define dstend x4
	#define tmp1 x5
	#define A_l x6
	#define A_h x7
	#define B_l x8
	#define B_h x9
	#define C_l x10
	#define C_h x11
	#define D_l x12
	#define D_h x13
	#define E_l count
	#define E_h tmp1

	/* All memmoves up to 96 bytes are done by memcpy as it supports overlaps.
	Larger backwards copies are also handled by memcpy. The only remaining
	case is forward large copies. The destination is aligned, and an
	unrolled loop processes 64 bytes per iteration.
	*/

	def_fn memmove, 6
	sub tmp1, dstin, src
	cmp count, 96
	ccmp tmp1, count, 2, hi
	b.hs memcpy

	cbz tmp1, 3f
	add dstend, dstin, count
	add srcend, src, count

	/* Align dstend to 16 byte alignment so that we don't cross cache line
	boundaries on both loads and stores. There are at least 96 bytes
	to copy, so copy 16 bytes unaligned and then align. The loop
	copies 64 bytes per iteration and prefetches one iteration ahead. */

	and tmp1, dstend, 15
	ldp D_l, D_h, [srcend, -16]
	sub srcend, srcend, tmp1
	sub count, count, tmp1
	ldp A_l, A_h, [srcend, -16]
	stp D_l, D_h, [dstend, -16]
	ldp B_l, B_h, [srcend, -32]
	ldp C_l, C_h, [srcend, -48]
	ldp D_l, D_h, [srcend, -64]!
	sub dstend, dstend, tmp1
	subs count, count, 128
	b.ls 2f
	nop
	1:
	stp A_l, A_h, [dstend, -16]
	ldp A_l, A_h, [srcend, -16]
	stp B_l, B_h, [dstend, -32]
	ldp B_l, B_h, [srcend, -32]
	stp C_l, C_h, [dstend, -48]
	ldp C_l, C_h, [srcend, -48]
	stp D_l, D_h, [dstend, -64]!
	ldp D_l, D_h, [srcend, -64]!
	subs count, count, 64
	b.hi 1b

	/* Write the last full set of 64 bytes. The remainder is at most 64
	bytes, so it is safe to always copy 64 bytes from the start even if
	there is just 1 byte left. */
	2:
	ldp E_l, E_h, [src, 48]
	stp A_l, A_h, [dstend, -16]
	ldp A_l, A_h, [src, 32]
	stp B_l, B_h, [dstend, -32]
	ldp B_l, B_h, [src, 16]
	stp C_l, C_h, [dstend, -48]
	ldp C_l, C_h, [src]
	stp D_l, D_h, [dstend, -64]
	stp E_l, E_h, [dstin, 48]
	stp A_l, A_h, [dstin, 32]
	stp B_l, B_h, [dstin, 16]
	stp C_l, C_h, [dstin]
	3: ret

	.size memmove, . - memmove