glibc/sysdeps/arm/memcpy.S

355 lines
7.9 KiB
ArmAsm

/* Copyright (C) 2006-2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by MontaVista Software, Inc. (written by Nicolas Pitre)
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/>. */
/* Thumb requires excessive IT insns here. */
#define NO_THUMB
#include <sysdep.h>
#include <arm-features.h>
/*
* Data preload for architectures that support it (ARM V5TE and above)
*/
#if (!defined (__ARM_ARCH_2__) && !defined (__ARM_ARCH_3__) \
&& !defined (__ARM_ARCH_3M__) && !defined (__ARM_ARCH_4__) \
&& !defined (__ARM_ARCH_4T__) && !defined (__ARM_ARCH_5__) \
&& !defined (__ARM_ARCH_5T__))
#define PLD(code...) code
#else
#define PLD(code...)
#endif
/*
* This can be used to enable code to cacheline align the source pointer.
* Experiments on tested architectures (StrongARM and XScale) didn't show
* this a worthwhile thing to do. That might be different in the future.
*/
//#define CALGN(code...) code
#define CALGN(code...)
/*
* Endian independent macros for shifting bytes within registers.
*/
#ifndef __ARMEB__
#define PULL lsr
#define PUSH lsl
#else
#define PULL lsl
#define PUSH lsr
#endif
.text
.syntax unified
/* Prototype: void *memcpy(void *dest, const void *src, size_t n); */
ENTRY(memcpy)
push {r0, r4, lr}
cfi_adjust_cfa_offset (12)
cfi_rel_offset (r4, 4)
cfi_rel_offset (lr, 8)
cfi_remember_state
subs r2, r2, #4
blt 8f
ands ip, r0, #3
PLD( sfi_pld r1, #0 )
bne 9f
ands ip, r1, #3
bne 10f
1: subs r2, r2, #(28)
push {r5 - r8}
cfi_adjust_cfa_offset (16)
cfi_rel_offset (r5, 0)
cfi_rel_offset (r6, 4)
cfi_rel_offset (r7, 8)
cfi_rel_offset (r8, 12)
blt 5f
CALGN( ands ip, r1, #31 )
CALGN( rsb r3, ip, #32 )
CALGN( sbcsne r4, r3, r2 ) @ C is always set here
CALGN( bcs 2f )
CALGN( adr r4, 6f )
CALGN( subs r2, r2, r3 ) @ C gets set
#ifndef ARM_ALWAYS_BX
CALGN( add pc, r4, ip, lsl #(ARM_BX_ALIGN_LOG2 - 2))
#else
CALGN( add r4, r4, ip, lsl #(ARM_BX_ALIGN_LOG2 - 2))
CALGN( bx r4 )
#endif
PLD( sfi_pld r1, #0 )
2: PLD( subs r2, r2, #96 )
PLD( sfi_pld r1, #28 )
PLD( blt 4f )
PLD( sfi_pld r1, #60 )
PLD( sfi_pld r1, #92 )
3: PLD( sfi_pld r1, #124 )
4: sfi_breg r1, \
ldmia \B!, {r3, r4, r5, r6, r7, r8, ip, lr}
subs r2, r2, #32
sfi_breg r0, \
stmia \B!, {r3, r4, r5, r6, r7, r8, ip, lr}
bge 3b
PLD( cmn r2, #96 )
PLD( bge 4b )
5: ands ip, r2, #28
rsb ip, ip, #32
#ifndef ARM_ALWAYS_BX
/* C is always clear here. */
addne pc, pc, ip, lsl #(ARM_BX_ALIGN_LOG2 - 2)
b 7f
#else
beq 7f
push {r10}
cfi_adjust_cfa_offset (4)
cfi_rel_offset (r10, 0)
0: add r10, pc, ip, lsl #(ARM_BX_ALIGN_LOG2 - 2)
/* If alignment is not perfect, then there will be some
padding (nop) instructions between this BX and label 6.
The computation above assumed that two instructions
later is exactly the right spot. */
add r10, #(6f - (0b + PC_OFS))
bx r10
#endif
.p2align ARM_BX_ALIGN_LOG2
6: nop
.p2align ARM_BX_ALIGN_LOG2
sfi_breg r1, \
ldr r3, [\B], #4
.p2align ARM_BX_ALIGN_LOG2
sfi_breg r1, \
ldr r4, [\B], #4
.p2align ARM_BX_ALIGN_LOG2
sfi_breg r1, \
ldr r5, [\B], #4
.p2align ARM_BX_ALIGN_LOG2
sfi_breg r1, \
ldr r6, [\B], #4
.p2align ARM_BX_ALIGN_LOG2
sfi_breg r1, \
ldr r7, [\B], #4
.p2align ARM_BX_ALIGN_LOG2
sfi_breg r1, \
ldr r8, [\B], #4
.p2align ARM_BX_ALIGN_LOG2
sfi_breg r1, \
ldr lr, [\B], #4
#ifndef ARM_ALWAYS_BX
add pc, pc, ip, lsl #(ARM_BX_ALIGN_LOG2 - 2)
nop
#else
0: add r10, pc, ip, lsl #(ARM_BX_ALIGN_LOG2 - 2)
/* If alignment is not perfect, then there will be some
padding (nop) instructions between this BX and label 66.
The computation above assumed that two instructions
later is exactly the right spot. */
add r10, #(66f - (0b + PC_OFS))
bx r10
#endif
.p2align ARM_BX_ALIGN_LOG2
66: nop
.p2align ARM_BX_ALIGN_LOG2
sfi_breg r0, \
str r3, [\B], #4
.p2align ARM_BX_ALIGN_LOG2
sfi_breg r0, \
str r4, [\B], #4
.p2align ARM_BX_ALIGN_LOG2
sfi_breg r0, \
str r5, [\B], #4
.p2align ARM_BX_ALIGN_LOG2
sfi_breg r0, \
str r6, [\B], #4
.p2align ARM_BX_ALIGN_LOG2
sfi_breg r0, \
str r7, [\B], #4
.p2align ARM_BX_ALIGN_LOG2
sfi_breg r0, \
str r8, [\B], #4
.p2align ARM_BX_ALIGN_LOG2
sfi_breg r0, \
str lr, [\B], #4
#ifdef ARM_ALWAYS_BX
pop {r10}
cfi_adjust_cfa_offset (-4)
cfi_restore (r10)
#endif
CALGN( bcs 2b )
7: pop {r5 - r8}
cfi_adjust_cfa_offset (-16)
cfi_restore (r5)
cfi_restore (r6)
cfi_restore (r7)
cfi_restore (r8)
8: movs r2, r2, lsl #31
sfi_breg r1, \
ldrbne r3, [\B], #1
sfi_breg r1, \
ldrbcs r4, [\B], #1
sfi_breg r1, \
ldrbcs ip, [\B]
sfi_breg r0, \
strbne r3, [\B], #1
sfi_breg r0, \
strbcs r4, [\B], #1
sfi_breg r0, \
strbcs ip, [\B]
#if ((defined (__ARM_ARCH_4T__) && defined(__THUMB_INTERWORK__)) \
|| defined (ARM_ALWAYS_BX))
pop {r0, r4, lr}
cfi_adjust_cfa_offset (-12)
cfi_restore (r4)
cfi_restore (lr)
bx lr
#else
pop {r0, r4, pc}
#endif
cfi_restore_state
9: rsb ip, ip, #4
cmp ip, #2
sfi_breg r1, \
ldrbgt r3, [\B], #1
sfi_breg r1, \
ldrbge r4, [\B], #1
sfi_breg r1, \
ldrb lr, [\B], #1
sfi_breg r0, \
strbgt r3, [\B], #1
sfi_breg r0, \
strbge r4, [\B], #1
subs r2, r2, ip
sfi_breg r0, \
strb lr, [\B], #1
blt 8b
ands ip, r1, #3
beq 1b
10: bic r1, r1, #3
cmp ip, #2
sfi_breg r1, \
ldr lr, [\B], #4
beq 17f
bgt 18f
.macro forward_copy_shift pull push
subs r2, r2, #28
blt 14f
CALGN( ands ip, r1, #31 )
CALGN( rsb ip, ip, #32 )
CALGN( sbcsne r4, ip, r2 ) @ C is always set here
CALGN( subcc r2, r2, ip )
CALGN( bcc 15f )
11: push {r5 - r8, r10}
cfi_adjust_cfa_offset (20)
cfi_rel_offset (r5, 0)
cfi_rel_offset (r6, 4)
cfi_rel_offset (r7, 8)
cfi_rel_offset (r8, 12)
cfi_rel_offset (r10, 16)
PLD( sfi_pld r1, #0 )
PLD( subs r2, r2, #96 )
PLD( sfi_pld r1, #28 )
PLD( blt 13f )
PLD( sfi_pld r1, #60 )
PLD( sfi_pld r1, #92 )
12: PLD( sfi_pld r1, #124 )
13: sfi_breg r1, \
ldmia \B!, {r4, r5, r6, r7}
mov r3, lr, PULL #\pull
subs r2, r2, #32
sfi_breg r1, \
ldmia \B!, {r8, r10, ip, lr}
orr r3, r3, r4, PUSH #\push
mov r4, r4, PULL #\pull
orr r4, r4, r5, PUSH #\push
mov r5, r5, PULL #\pull
orr r5, r5, r6, PUSH #\push
mov r6, r6, PULL #\pull
orr r6, r6, r7, PUSH #\push
mov r7, r7, PULL #\pull
orr r7, r7, r8, PUSH #\push
mov r8, r8, PULL #\pull
orr r8, r8, r10, PUSH #\push
mov r10, r10, PULL #\pull
orr r10, r10, ip, PUSH #\push
mov ip, ip, PULL #\pull
orr ip, ip, lr, PUSH #\push
sfi_breg r0, \
stmia \B!, {r3, r4, r5, r6, r7, r8, r10, ip}
bge 12b
PLD( cmn r2, #96 )
PLD( bge 13b )
pop {r5 - r8, r10}
cfi_adjust_cfa_offset (-20)
cfi_restore (r5)
cfi_restore (r6)
cfi_restore (r7)
cfi_restore (r8)
cfi_restore (r10)
14: ands ip, r2, #28
beq 16f
15: mov r3, lr, PULL #\pull
sfi_breg r1, \
ldr lr, [\B], #4
subs ip, ip, #4
orr r3, r3, lr, PUSH #\push
sfi_breg r0, \
str r3, [\B], #4
bgt 15b
CALGN( cmp r2, #0 )
CALGN( bge 11b )
16: sub r1, r1, #(\push / 8)
b 8b
.endm
forward_copy_shift pull=8 push=24
17: forward_copy_shift pull=16 push=16
18: forward_copy_shift pull=24 push=8
END(memcpy)
libc_hidden_builtin_def (memcpy)