/*
* memcpy - copy memory area
*
* Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
* See https://llvm.org/LICENSE.txt for license information.
* SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
*/
/*
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
*/
#include "../asmdefs.h"
.syntax unified
/* This implementation requires ARM state. */
.arm
#ifdef __ARM_NEON__
.fpu neon
.arch armv7-a
# define FRAME_SIZE 4
# define USE_VFP
# define USE_NEON
#elif !defined (__SOFTFP__)
.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
ENTRY (__memcpy_arm)
mov dst, dstin /* Preserve dstin, we need to return it. */
cmp count, #64
bge L(cpy_not_short)
/* Deal with small copies quickly by dropping straight into the
exit block. */
L(tail63unaligned):
#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
L(cpy_not_short):
/* At least 64 bytes to copy, but don't know the alignment yet. */
str tmp2, [sp, #-FRAME_SIZE]!
and tmp2, src, #7
and tmp1, dst, #7
cmp tmp1, tmp2
bne L(cpy_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 64-bit alignment, but we may
still need to pre-copy some bytes to get to natural alignment.
We bring SRC and 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 L(tail63aligned)
cmp tmp2, #512
bge L(cpy_body_long)
L(cpy_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 L(done)
L(tail63aligned): /* 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
L(tail63aligned): /* Count in tmp2. */
/* Copy up to 7 d-words of data. Similar to Ltail63unaligned, but
we know that the src and dest are 64-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]
L(done):
ldr tmp2, [sp], #FRAME_SIZE
bx lr
L(cpy_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 L(cpy_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 L(tail63aligned)
ldr tmp2, [sp], #FRAME_SIZE
bx lr
#endif
L(cpy_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 L(tail63unaligned)
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 L(tail63unaligned)
bx lr
END (__memcpy_arm)
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