231 lines
6.9 KiB
ArmAsm
231 lines
6.9 KiB
ArmAsm
/* Copyright (c) 2012-2013, Linaro Limited
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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* Neither the name of the Linaro nor the
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names of its contributors may be used to endorse or promote products
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derived from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
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/*
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* Copyright (c) 2015 ARM Ltd
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the company may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY ARM LTD ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL ARM LTD BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
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* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/* Assumptions:
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*
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* ARMv8-a, AArch64, unaligned accesses.
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*
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*/
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#if (defined (__OPTIMIZE_SIZE__) || defined (PREFER_SIZE_OVER_SPEED))
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/* See memcpy-stub.c */
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#else
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#define dstin x0
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#define src x1
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#define count x2
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#define dst x3
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#define srcend x4
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#define dstend x5
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#define A_l x6
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#define A_lw w6
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#define A_h x7
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#define A_hw w7
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#define B_l x8
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#define B_lw w8
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#define B_h x9
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#define C_l x10
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#define C_h x11
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#define D_l x12
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#define D_h x13
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#define E_l src
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#define E_h count
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#define F_l srcend
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#define F_h dst
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#define tmp1 x9
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#define L(l) .L ## l
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.macro def_fn f p2align=0
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.text
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.p2align \p2align
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.global \f
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.type \f, %function
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\f:
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.endm
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/* Copies are split into 3 main cases: small copies of up to 16 bytes,
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medium copies of 17..96 bytes which are fully unrolled. Large copies
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of more than 96 bytes align the destination and use an unrolled loop
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processing 64 bytes per iteration.
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Small and medium copies read all data before writing, allowing any
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kind of overlap, and memmove tailcalls memcpy for these cases as
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well as non-overlapping copies.
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*/
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def_fn memcpy p2align=6
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prfm PLDL1KEEP, [src]
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add srcend, src, count
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add dstend, dstin, count
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cmp count, 16
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b.ls L(copy16)
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cmp count, 96
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b.hi L(copy_long)
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/* Medium copies: 17..96 bytes. */
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sub tmp1, count, 1
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ldp A_l, A_h, [src]
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tbnz tmp1, 6, L(copy96)
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ldp D_l, D_h, [srcend, -16]
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tbz tmp1, 5, 1f
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ldp B_l, B_h, [src, 16]
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ldp C_l, C_h, [srcend, -32]
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stp B_l, B_h, [dstin, 16]
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stp C_l, C_h, [dstend, -32]
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1:
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stp A_l, A_h, [dstin]
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stp D_l, D_h, [dstend, -16]
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ret
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.p2align 4
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/* Small copies: 0..16 bytes. */
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L(copy16):
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cmp count, 8
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b.lo 1f
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ldr A_l, [src]
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ldr A_h, [srcend, -8]
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str A_l, [dstin]
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str A_h, [dstend, -8]
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ret
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.p2align 4
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1:
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tbz count, 2, 1f
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ldr A_lw, [src]
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ldr A_hw, [srcend, -4]
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str A_lw, [dstin]
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str A_hw, [dstend, -4]
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ret
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/* Copy 0..3 bytes. Use a branchless sequence that copies the same
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byte 3 times if count==1, or the 2nd byte twice if count==2. */
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1:
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cbz count, 2f
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lsr tmp1, count, 1
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ldrb A_lw, [src]
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ldrb A_hw, [srcend, -1]
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ldrb B_lw, [src, tmp1]
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strb A_lw, [dstin]
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strb B_lw, [dstin, tmp1]
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strb A_hw, [dstend, -1]
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2: ret
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.p2align 4
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/* Copy 64..96 bytes. Copy 64 bytes from the start and
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32 bytes from the end. */
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L(copy96):
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ldp B_l, B_h, [src, 16]
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ldp C_l, C_h, [src, 32]
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ldp D_l, D_h, [src, 48]
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ldp E_l, E_h, [srcend, -32]
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ldp F_l, F_h, [srcend, -16]
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stp A_l, A_h, [dstin]
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stp B_l, B_h, [dstin, 16]
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stp C_l, C_h, [dstin, 32]
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stp D_l, D_h, [dstin, 48]
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stp E_l, E_h, [dstend, -32]
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stp F_l, F_h, [dstend, -16]
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ret
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/* Align DST to 16 byte alignment so that we don't cross cache line
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boundaries on both loads and stores. There are at least 96 bytes
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to copy, so copy 16 bytes unaligned and then align. The loop
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copies 64 bytes per iteration and prefetches one iteration ahead. */
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.p2align 4
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L(copy_long):
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and tmp1, dstin, 15
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bic dst, dstin, 15
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ldp D_l, D_h, [src]
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sub src, src, tmp1
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add count, count, tmp1 /* Count is now 16 too large. */
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ldp A_l, A_h, [src, 16]
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stp D_l, D_h, [dstin]
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ldp B_l, B_h, [src, 32]
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ldp C_l, C_h, [src, 48]
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ldp D_l, D_h, [src, 64]!
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subs count, count, 128 + 16 /* Test and readjust count. */
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b.ls 2f
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1:
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stp A_l, A_h, [dst, 16]
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ldp A_l, A_h, [src, 16]
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stp B_l, B_h, [dst, 32]
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ldp B_l, B_h, [src, 32]
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stp C_l, C_h, [dst, 48]
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ldp C_l, C_h, [src, 48]
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stp D_l, D_h, [dst, 64]!
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ldp D_l, D_h, [src, 64]!
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subs count, count, 64
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b.hi 1b
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/* Write the last full set of 64 bytes. The remainder is at most 64
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bytes, so it is safe to always copy 64 bytes from the end even if
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there is just 1 byte left. */
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2:
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ldp E_l, E_h, [srcend, -64]
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stp A_l, A_h, [dst, 16]
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ldp A_l, A_h, [srcend, -48]
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stp B_l, B_h, [dst, 32]
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ldp B_l, B_h, [srcend, -32]
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stp C_l, C_h, [dst, 48]
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ldp C_l, C_h, [srcend, -16]
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stp D_l, D_h, [dst, 64]
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stp E_l, E_h, [dstend, -64]
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stp A_l, A_h, [dstend, -48]
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stp B_l, B_h, [dstend, -32]
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stp C_l, C_h, [dstend, -16]
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ret
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.size memcpy, . - memcpy
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#endif
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