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/*
* Copyright (C) 2008 The Android Open Source Project
* 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.
*
* 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 OWNER 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.
*/
/*
* This code assumes it is running on a processor that supports all arm v7
* instructions, that supports neon instructions, and that has a 32 byte
* cache line.
*/
.text
.fpu neon
#define CACHE_LINE_SIZE 32
.globl memcpy
.type memcpy,%function
memcpy:
.fnstart
.save {r0, lr}
/* start preloading as early as possible */
pld [r1, #(CACHE_LINE_SIZE * 0)]
stmfd sp!, {r0, lr}
pld [r1, #(CACHE_LINE_SIZE * 2)]
// Check so divider is at least 16 bytes, needed for alignment code.
cmp r2, #16
blo 5f
/* check if buffers are aligned. If so, run arm-only version */
eor r3, r0, r1
ands r3, r3, #0x3
beq 11f
/* Check the upper size limit for Neon unaligned memory access in memcpy */
cmp r2, #224
blo 3f
/* align destination to 16 bytes for the write-buffer */
rsb r3, r0, #0
ands r3, r3, #0xF
beq 3f
/* copy up to 15-bytes (count in r3) */
sub r2, r2, r3
movs ip, r3, lsl #31
ldrmib lr, [r1], #1
strmib lr, [r0], #1
ldrcsb ip, [r1], #1
ldrcsb lr, [r1], #1
strcsb ip, [r0], #1
strcsb lr, [r0], #1
movs ip, r3, lsl #29
bge 1f
// copies 4 bytes, destination 32-bits aligned
vld1.32 {d0[0]}, [r1]!
vst1.32 {d0[0]}, [r0, :32]!
1: bcc 2f
// copies 8 bytes, destination 64-bits aligned
vld1.8 {d0}, [r1]!
vst1.8 {d0}, [r0, :64]!
2:
/* preload immediately the next cache line, which we may need */
pld [r1, #(CACHE_LINE_SIZE * 0)]
pld [r1, #(CACHE_LINE_SIZE * 2)]
3:
/* make sure we have at least 64 bytes to copy */
subs r2, r2, #64
blo 2f
/* preload all the cache lines we need */
pld [r1, #(CACHE_LINE_SIZE * 4)]
pld [r1, #(CACHE_LINE_SIZE * 6)]
1: /* The main loop copies 64 bytes at a time */
vld1.8 {d0 - d3}, [r1]!
vld1.8 {d4 - d7}, [r1]!
pld [r1, #(CACHE_LINE_SIZE * 6)]
subs r2, r2, #64
vst1.8 {d0 - d3}, [r0]!
vst1.8 {d4 - d7}, [r0]!
bhs 1b
2: /* fix-up the remaining count and make sure we have >= 32 bytes left */
add r2, r2, #64
subs r2, r2, #32
blo 4f
3: /* 32 bytes at a time. These cache lines were already preloaded */
vld1.8 {d0 - d3}, [r1]!
subs r2, r2, #32
vst1.8 {d0 - d3}, [r0]!
bhs 3b
4: /* less than 32 left */
add r2, r2, #32
tst r2, #0x10
beq 5f
// copies 16 bytes, 128-bits aligned
vld1.8 {d0, d1}, [r1]!
vst1.8 {d0, d1}, [r0]!
5: /* copy up to 15-bytes (count in r2) */
movs ip, r2, lsl #29
bcc 1f
vld1.8 {d0}, [r1]!
vst1.8 {d0}, [r0]!
1: bge 2f
vld1.32 {d0[0]}, [r1]!
vst1.32 {d0[0]}, [r0]!
2: movs ip, r2, lsl #31
ldrmib r3, [r1], #1
ldrcsb ip, [r1], #1
ldrcsb lr, [r1], #1
strmib r3, [r0], #1
strcsb ip, [r0], #1
strcsb lr, [r0], #1
ldmfd sp!, {r0, lr}
bx lr
11:
/* Simple arm-only copy loop to handle aligned copy operations */
stmfd sp!, {r4, r5, r6, r7, r8}
pld [r1, #(CACHE_LINE_SIZE * 4)]
/* Check alignment */
rsb r3, r1, #0
ands r3, #3
beq 2f
/* align source to 32 bits. We need to insert 2 instructions between
* a ldr[b|h] and str[b|h] because byte and half-word instructions
* stall 2 cycles.
*/
movs r12, r3, lsl #31
sub r2, r2, r3 /* we know that r3 <= r2 because r2 >= 4 */
ldrmib r3, [r1], #1
ldrcsb r4, [r1], #1
ldrcsb r5, [r1], #1
strmib r3, [r0], #1
strcsb r4, [r0], #1
strcsb r5, [r0], #1
2:
subs r2, r2, #64
blt 4f
3: /* Main copy loop, copying 64 bytes at a time */
pld [r1, #(CACHE_LINE_SIZE * 8)]
ldmia r1!, {r3, r4, r5, r6, r7, r8, r12, lr}
stmia r0!, {r3, r4, r5, r6, r7, r8, r12, lr}
ldmia r1!, {r3, r4, r5, r6, r7, r8, r12, lr}
stmia r0!, {r3, r4, r5, r6, r7, r8, r12, lr}
subs r2, r2, #64
bge 3b
4: /* Check if there are > 32 bytes left */
adds r2, r2, #64
subs r2, r2, #32
blt 5f
/* Copy 32 bytes */
ldmia r1!, {r3, r4, r5, r6, r7, r8, r12, lr}
stmia r0!, {r3, r4, r5, r6, r7, r8, r12, lr}
subs r2, #32
5: /* Handle any remaining bytes */
adds r2, #32
beq 6f
movs r12, r2, lsl #28
ldmcsia r1!, {r3, r4, r5, r6} /* 16 bytes */
ldmmiia r1!, {r7, r8} /* 8 bytes */
stmcsia r0!, {r3, r4, r5, r6}
stmmiia r0!, {r7, r8}
movs r12, r2, lsl #30
ldrcs r3, [r1], #4 /* 4 bytes */
ldrmih r4, [r1], #2 /* 2 bytes */
strcs r3, [r0], #4
strmih r4, [r0], #2
tst r2, #0x1
ldrneb r3, [r1] /* last byte */
strneb r3, [r0]
6:
ldmfd sp!, {r4, r5, r6, r7, r8}
ldmfd sp!, {r0, pc}
.fnend
.size memcpy, .-memcpy
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