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/*
* Copyright (C) 2013 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.
*/
#include <machine/cpu-features.h>
#include <private/bionic_asm.h>
#include <private/libc_events.h>
/*
* Optimized memset() for ARM.
*
* memset() returns its first argument.
*/
.fpu neon
.syntax unified
ENTRY(__memset_chk)
cmp r2, r3
bls .L_done
// Preserve lr for backtrace.
push {lr}
.cfi_def_cfa_offset 4
.cfi_rel_offset lr, 0
ldr r0, error_message
ldr r1, error_code
1:
add r0, pc
bl __fortify_chk_fail
error_code:
.word BIONIC_EVENT_MEMSET_BUFFER_OVERFLOW
error_message:
.word error_string-(1b+8)
END(__memset_chk)
ENTRY(bzero)
mov r2, r1
mov r1, #0
.L_done:
// Fall through to memset...
END(bzero)
ENTRY(memset)
stmfd sp!, {r0}
.cfi_def_cfa_offset 4
.cfi_rel_offset r0, 0
// The new algorithm is slower for copies < 16 so use the old
// neon code in that case.
cmp r2, #16
blo .L_set_less_than_16_unknown_align
// Use strd which requires an even and odd register so move the
// values so that:
// r0 and r1 contain the memset value
// r2 is the number of bytes to set
// r3 is the destination pointer
mov r3, r0
// Copy the byte value in every byte of r1.
mov r1, r1, lsl #24
orr r1, r1, r1, lsr #8
orr r1, r1, r1, lsr #16
.L_check_alignment:
// Align destination to a double word to avoid the strd crossing
// a cache line boundary.
ands ip, r3, #7
bne .L_do_double_word_align
.L_double_word_aligned:
mov r0, r1
subs r2, #64
blo .L_set_less_than_64
1: // Main loop sets 64 bytes at a time.
.irp offset, #0, #8, #16, #24, #32, #40, #48, #56
strd r0, r1, [r3, \offset]
.endr
add r3, #64
subs r2, #64
bge 1b
.L_set_less_than_64:
// Restore r2 to the count of bytes left to set.
add r2, #64
lsls ip, r2, #27
bcc .L_set_less_than_32
// Set 32 bytes.
.irp offset, #0, #8, #16, #24
strd r0, r1, [r3, \offset]
.endr
add r3, #32
.L_set_less_than_32:
bpl .L_set_less_than_16
// Set 16 bytes.
.irp offset, #0, #8
strd r0, r1, [r3, \offset]
.endr
add r3, #16
.L_set_less_than_16:
// Less than 16 bytes to set.
lsls ip, r2, #29
bcc .L_set_less_than_8
// Set 8 bytes.
strd r0, r1, [r3], #8
.L_set_less_than_8:
bpl .L_set_less_than_4
// Set 4 bytes
str r1, [r3], #4
.L_set_less_than_4:
lsls ip, r2, #31
it ne
strbne r1, [r3], #1
itt cs
strbcs r1, [r3], #1
strbcs r1, [r3]
ldmfd sp!, {r0}
bx lr
.L_do_double_word_align:
rsb ip, ip, #8
sub r2, r2, ip
movs r0, ip, lsl #31
it mi
strbmi r1, [r3], #1
itt cs
strbcs r1, [r3], #1
strbcs r1, [r3], #1
// Dst is at least word aligned by this point.
cmp ip, #4
blo .L_double_word_aligned
str r1, [r3], #4
b .L_double_word_aligned
.L_set_less_than_16_unknown_align:
// Set up to 15 bytes.
vdup.8 d0, r1
movs ip, r2, lsl #29
bcc 1f
vst1.8 {d0}, [r0]!
1: bge 2f
vst1.32 {d0[0]}, [r0]!
2: movs ip, r2, lsl #31
it mi
strbmi r1, [r0], #1
itt cs
strbcs r1, [r0], #1
strbcs r1, [r0], #1
ldmfd sp!, {r0}
bx lr
END(memset)
.data
error_string:
.string "memset: prevented write past end of buffer"
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