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am e7ea9363: Merge "Add ARMv8 optimized string handling functions based on cortex-strings"

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* commit 'e7ea9363cb30d5c36c9333162c11b1e7b4f302b6':
  Add ARMv8 optimized string handling functions based on cortex-strings
This commit is contained in:
Elliott Hughes 2014-03-07 00:01:23 +00:00 committed by Android Git Automerger
commit 91a5272e6f
10 changed files with 1584 additions and 8 deletions
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10
libc/arch-arm64/arm64.mk
View File

@ -4,13 +4,8 @@ libc_common_src_files_arm64 := \
bionic/index.cpp \
bionic/memchr.c \
bionic/__memcmp16.cpp \
bionic/memcmp.c \
bionic/memcpy.cpp \
bionic/memmove.c \
bionic/memrchr.c \
bionic/memset.c \
bionic/strchr.cpp \
bionic/strnlen.c \
bionic/strrchr.cpp \
upstream-freebsd/lib/libc/string/wcscat.c \
upstream-freebsd/lib/libc/string/wcschr.c \
@ -21,13 +16,10 @@ libc_common_src_files_arm64 := \
upstream-freebsd/lib/libc/string/wmemcmp.c \
upstream-openbsd/lib/libc/string/bcopy.c \
upstream-openbsd/lib/libc/string/strcat.c \
upstream-openbsd/lib/libc/string/strcmp.c \
upstream-openbsd/lib/libc/string/strcpy.c \
upstream-openbsd/lib/libc/string/strlcat.c \
upstream-openbsd/lib/libc/string/strlcpy.c \
upstream-openbsd/lib/libc/string/strlen.c \
upstream-openbsd/lib/libc/string/strncat.c \
upstream-openbsd/lib/libc/string/strncmp.c \
upstream-openbsd/lib/libc/string/strncpy.c \
# Fortify implementations of libc functions.
@ -62,3 +54,5 @@ libc_crt_target_crtbegin_file_arm64 := \
libc_crt_target_crtbegin_so_file_arm64 := \
$(LOCAL_PATH)/arch-common/bionic/crtbegin_so.c
include $(LOCAL_PATH)/arch-arm64/generic/generic.mk

155
libc/arch-arm64/generic/bionic/memcmp.S Normal file
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@ -0,0 +1,155 @@
/* Copyright (c) 2014, Linaro Limited
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.
* Neither the name of the Linaro nor the
names of its contributors may be used to endorse or promote products
derived from this software without specific prior written permission.
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
HOLDER 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.
*/
/* Assumptions:
*
* ARMv8-a, AArch64
*/
#include <private/bionic_asm.h>
/* Parameters and result. */
#define src1 x0
#define src2 x1
#define limit x2
#define result x0
/* Internal variables. */
#define data1 x3
#define data1w w3
#define data2 x4
#define data2w w4
#define has_nul x5
#define diff x6
#define endloop x7
#define tmp1 x8
#define tmp2 x9
#define tmp3 x10
#define pos x11
#define limit_wd x12
#define mask x13
ENTRY(memcmp)
cbz limit, .Lret0
eor tmp1, src1, src2
tst tmp1, #7
b.ne .Lmisaligned8
ands tmp1, src1, #7
b.ne .Lmutual_align
add limit_wd, limit, #7
lsr limit_wd, limit_wd, #3
/* Start of performance-critical section -- one 64B cache line. */
.Lloop_aligned:
ldr data1, [src1], #8
ldr data2, [src2], #8
.Lstart_realigned:
subs limit_wd, limit_wd, #1
eor diff, data1, data2 /* Non-zero if differences found. */
csinv endloop, diff, xzr, ne /* Last Dword or differences. */
cbz endloop, .Lloop_aligned
/* End of performance-critical section -- one 64B cache line. */
/* Not reached the limit, must have found a diff. */
cbnz limit_wd, .Lnot_limit
/* Limit % 8 == 0 => all bytes significant. */
ands limit, limit, #7
b.eq .Lnot_limit
lsl limit, limit, #3 /* Bits -> bytes. */
mov mask, #~0
#ifdef __AARCH64EB__
lsr mask, mask, limit
#else
lsl mask, mask, limit
#endif
bic data1, data1, mask
bic data2, data2, mask
orr diff, diff, mask
.Lnot_limit:
#ifndef __AARCH64EB__
rev diff, diff
rev data1, data1
rev data2, data2
#endif
/* The MS-non-zero bit of DIFF marks either the first bit
that is different, or the end of the significant data.
Shifting left now will bring the critical information into the
top bits. */
clz pos, diff
lsl data1, data1, pos
lsl data2, data2, pos
/* But we need to zero-extend (char is unsigned) the value and then
perform a signed 32-bit subtraction. */
lsr data1, data1, #56
sub result, data1, data2, lsr #56
ret
.Lmutual_align:
/* Sources are mutually aligned, but are not currently at an
alignment boundary. Round down the addresses and then mask off
the bytes that precede the start point. */
bic src1, src1, #7
bic src2, src2, #7
add limit, limit, tmp1 /* Adjust the limit for the extra. */
lsl tmp1, tmp1, #3 /* Bytes beyond alignment -> bits. */
ldr data1, [src1], #8
neg tmp1, tmp1 /* Bits to alignment -64. */
ldr data2, [src2], #8
mov tmp2, #~0
#ifdef __AARCH64EB__
/* Big-endian. Early bytes are at MSB. */
lsl tmp2, tmp2, tmp1 /* Shift (tmp1 & 63). */
#else
/* Little-endian. Early bytes are at LSB. */
lsr tmp2, tmp2, tmp1 /* Shift (tmp1 & 63). */
#endif
add limit_wd, limit, #7
orr data1, data1, tmp2
orr data2, data2, tmp2
lsr limit_wd, limit_wd, #3
b .Lstart_realigned
.Lret0:
mov result, #0
ret
.p2align 6
.Lmisaligned8:
sub limit, limit, #1
1:
/* Perhaps we can do better than this. */
ldrb data1w, [src1], #1
ldrb data2w, [src2], #1
subs limit, limit, #1
ccmp data1w, data2w, #0, cs /* NZCV = 0b0000. */
b.eq 1b
sub result, data1, data2
ret
END(memcmp)

184
libc/arch-arm64/generic/bionic/memcpy.S Normal file
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@ -0,0 +1,184 @@
/* Copyright (c) 2012, Linaro Limited
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.
* Neither the name of the Linaro nor the
names of its contributors may be used to endorse or promote products
derived from this software without specific prior written permission.
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
HOLDER 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.
*/
/* Assumptions:
*
* ARMv8-a, AArch64
* Unaligned accesses
*
*/
#include <private/bionic_asm.h>
#define dstin x0
#define src x1
#define count x2
#define tmp1 x3
#define tmp1w w3
#define tmp2 x4
#define tmp2w w4
#define tmp3 x5
#define tmp3w w5
#define dst x6
#define A_l x7
#define A_h x8
#define B_l x9
#define B_h x10
#define C_l x11
#define C_h x12
#define D_l x13
#define D_h x14
ENTRY(memcpy)
mov dst, dstin
cmp count, #64
b.ge .Lcpy_not_short
cmp count, #15
b.le .Ltail15tiny
/* Deal with small copies quickly by dropping straight into the
* exit block. */
.Ltail63:
/* Copy up to 48 bytes of data. At this point we only need the
* bottom 6 bits of count to be accurate. */
ands tmp1, count, #0x30
b.eq .Ltail15
add dst, dst, tmp1
add src, src, tmp1
cmp tmp1w, #0x20
b.eq 1f
b.lt 2f
ldp A_l, A_h, [src, #-48]
stp A_l, A_h, [dst, #-48]
1:
ldp A_l, A_h, [src, #-32]
stp A_l, A_h, [dst, #-32]
2:
ldp A_l, A_h, [src, #-16]
stp A_l, A_h, [dst, #-16]
.Ltail15:
ands count, count, #15
beq 1f
add src, src, count
ldp A_l, A_h, [src, #-16]
add dst, dst, count
stp A_l, A_h, [dst, #-16]
1:
ret
.Ltail15tiny:
/* Copy up to 15 bytes of data. Does not assume additional data
being copied. */
tbz count, #3, 1f
ldr tmp1, [src], #8
str tmp1, [dst], #8
1:
tbz count, #2, 1f
ldr tmp1w, [src], #4
str tmp1w, [dst], #4
1:
tbz count, #1, 1f
ldrh tmp1w, [src], #2
strh tmp1w, [dst], #2
1:
tbz count, #0, 1f
ldrb tmp1w, [src]
strb tmp1w, [dst]
1:
ret
.Lcpy_not_short:
/* We don't much care about the alignment of DST, but we want SRC
* to be 128-bit (16 byte) aligned so that we don't cross cache line
* boundaries on both loads and stores. */
neg tmp2, src
ands tmp2, tmp2, #15 /* Bytes to reach alignment. */
b.eq 2f
sub count, count, tmp2
/* Copy more data than needed; it's faster than jumping
* around copying sub-Quadword quantities. We know that
* it can't overrun. */
ldp A_l, A_h, [src]
add src, src, tmp2
stp A_l, A_h, [dst]
add dst, dst, tmp2
/* There may be less than 63 bytes to go now. */
cmp count, #63
b.le .Ltail63
2:
subs count, count, #128
b.ge .Lcpy_body_large
/* Less than 128 bytes to copy, so handle 64 here and then jump
* to the tail. */
ldp A_l, A_h, [src]
ldp B_l, B_h, [src, #16]
ldp C_l, C_h, [src, #32]
ldp D_l, D_h, [src, #48]
stp A_l, A_h, [dst]
stp B_l, B_h, [dst, #16]
stp C_l, C_h, [dst, #32]
stp D_l, D_h, [dst, #48]
tst count, #0x3f
add src, src, #64
add dst, dst, #64
b.ne .Ltail63
ret
/* Critical loop. Start at a new cache line boundary. Assuming
* 64 bytes per line this ensures the entire loop is in one line. */
.p2align 6
.Lcpy_body_large:
/* There are at least 128 bytes to copy. */
ldp A_l, A_h, [src, #0]
sub dst, dst, #16 /* Pre-bias. */
ldp B_l, B_h, [src, #16]
ldp C_l, C_h, [src, #32]
ldp D_l, D_h, [src, #48]! /* src += 64 - Pre-bias. */
1:
stp A_l, A_h, [dst, #16]
ldp A_l, A_h, [src, #16]
stp B_l, B_h, [dst, #32]
ldp B_l, B_h, [src, #32]
stp C_l, C_h, [dst, #48]
ldp C_l, C_h, [src, #48]
stp D_l, D_h, [dst, #64]!
ldp D_l, D_h, [src, #64]!
subs count, count, #64
b.ge 1b
stp A_l, A_h, [dst, #16]
stp B_l, B_h, [dst, #32]
stp C_l, C_h, [dst, #48]
stp D_l, D_h, [dst, #64]
add src, src, #16
add dst, dst, #64 + 16
tst count, #0x3f
b.ne .Ltail63
ret
END(memcpy)

319
libc/arch-arm64/generic/bionic/memmove.S Normal file
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@ -0,0 +1,319 @@
/* Copyright (c) 2014, Linaro Limited
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.
* Neither the name of the Linaro nor the
names of its contributors may be used to endorse or promote products
derived from this software without specific prior written permission.
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
HOLDER 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.
*/
/* Assumptions:
*
* ARMv8-a, AArch64
* Unaligned accesses
*/
#include <private/bionic_asm.h>
/* Parameters and result. */
#define dstin x0
#define src x1
#define count x2
#define tmp1 x3
#define tmp1w w3
#define tmp2 x4
#define tmp2w w4
#define tmp3 x5
#define tmp3w w5
#define dst x6
#define A_l x7
#define A_h x8
#define B_l x9
#define B_h x10
#define C_l x11
#define C_h x12
#define D_l x13
#define D_h x14
ENTRY(memmove)
cmp dstin, src
b.lo .Ldownwards
add tmp1, src, count
cmp dstin, tmp1
b.hs memcpy /* No overlap. */
/* Upwards move with potential overlap.
* Need to move from the tail backwards. SRC and DST point one
* byte beyond the remaining data to move. */
add dst, dstin, count
add src, src, count
cmp count, #64
b.ge .Lmov_not_short_up
/* Deal with small moves quickly by dropping straight into the
* exit block. */
.Ltail63up:
/* Move up to 48 bytes of data. At this point we only need the
* bottom 6 bits of count to be accurate. */
ands tmp1, count, #0x30
b.eq .Ltail15up
sub dst, dst, tmp1
sub src, src, tmp1
cmp tmp1w, #0x20
b.eq 1f
b.lt 2f
ldp A_l, A_h, [src, #32]
stp A_l, A_h, [dst, #32]
1:
ldp A_l, A_h, [src, #16]
stp A_l, A_h, [dst, #16]
2:
ldp A_l, A_h, [src]
stp A_l, A_h, [dst]
.Ltail15up:
/* Move up to 15 bytes of data. Does not assume additional data
* being moved. */
tbz count, #3, 1f
ldr tmp1, [src, #-8]!
str tmp1, [dst, #-8]!
1:
tbz count, #2, 1f
ldr tmp1w, [src, #-4]!
str tmp1w, [dst, #-4]!
1:
tbz count, #1, 1f
ldrh tmp1w, [src, #-2]!
strh tmp1w, [dst, #-2]!
1:
tbz count, #0, 1f
ldrb tmp1w, [src, #-1]
strb tmp1w, [dst, #-1]
1:
ret
.Lmov_not_short_up:
/* We don't much care about the alignment of DST, but we want SRC
* to be 128-bit (16 byte) aligned so that we don't cross cache line
* boundaries on both loads and stores. */
ands tmp2, src, #15 /* Bytes to reach alignment. */
b.eq 2f
sub count, count, tmp2
/* Move enough data to reach alignment; unlike memcpy, we have to
* be aware of the overlap, which means we can't move data twice. */
tbz tmp2, #3, 1f
ldr tmp1, [src, #-8]!
str tmp1, [dst, #-8]!
1:
tbz tmp2, #2, 1f
ldr tmp1w, [src, #-4]!
str tmp1w, [dst, #-4]!
1:
tbz tmp2, #1, 1f
ldrh tmp1w, [src, #-2]!
strh tmp1w, [dst, #-2]!
1:
tbz tmp2, #0, 1f
ldrb tmp1w, [src, #-1]!
strb tmp1w, [dst, #-1]!
1:
/* There may be less than 63 bytes to go now. */
cmp count, #63
b.le .Ltail63up
2:
subs count, count, #128
b.ge .Lmov_body_large_up
/* Less than 128 bytes to move, so handle 64 here and then jump
* to the tail. */
ldp A_l, A_h, [src, #-64]!
ldp B_l, B_h, [src, #16]
ldp C_l, C_h, [src, #32]
ldp D_l, D_h, [src, #48]
stp A_l, A_h, [dst, #-64]!
stp B_l, B_h, [dst, #16]
stp C_l, C_h, [dst, #32]
stp D_l, D_h, [dst, #48]
tst count, #0x3f
b.ne .Ltail63up
ret
/* Critical loop. Start at a new Icache line boundary. Assuming
* 64 bytes per line this ensures the entire loop is in one line. */
.p2align 6
.Lmov_body_large_up:
/* There are at least 128 bytes to move. */
ldp A_l, A_h, [src, #-16]
ldp B_l, B_h, [src, #-32]
ldp C_l, C_h, [src, #-48]
ldp D_l, D_h, [src, #-64]!
1:
stp A_l, A_h, [dst, #-16]
ldp A_l, A_h, [src, #-16]
stp B_l, B_h, [dst, #-32]
ldp B_l, B_h, [src, #-32]
stp C_l, C_h, [dst, #-48]
ldp C_l, C_h, [src, #-48]
stp D_l, D_h, [dst, #-64]!
ldp D_l, D_h, [src, #-64]!
subs count, count, #64
b.ge 1b
stp A_l, A_h, [dst, #-16]
stp B_l, B_h, [dst, #-32]
stp C_l, C_h, [dst, #-48]
stp D_l, D_h, [dst, #-64]!
tst count, #0x3f
b.ne .Ltail63up
ret
.Ldownwards:
/* For a downwards move we can safely use memcpy provided that
* DST is more than 16 bytes away from SRC. */
sub tmp1, src, #16
cmp dstin, tmp1
b.ls memcpy /* May overlap, but not critically. */
mov dst, dstin /* Preserve DSTIN for return value. */
cmp count, #64
b.ge .Lmov_not_short_down
/* Deal with small moves quickly by dropping straight into the
* exit block. */
.Ltail63down:
/* Move up to 48 bytes of data. At this point we only need the
* bottom 6 bits of count to be accurate. */
ands tmp1, count, #0x30
b.eq .Ltail15down
add dst, dst, tmp1
add src, src, tmp1
cmp tmp1w, #0x20
b.eq 1f
b.lt 2f
ldp A_l, A_h, [src, #-48]
stp A_l, A_h, [dst, #-48]
1:
ldp A_l, A_h, [src, #-32]
stp A_l, A_h, [dst, #-32]
2:
ldp A_l, A_h, [src, #-16]
stp A_l, A_h, [dst, #-16]
.Ltail15down:
/* Move up to 15 bytes of data. Does not assume additional data
being moved. */
tbz count, #3, 1f
ldr tmp1, [src], #8
str tmp1, [dst], #8
1:
tbz count, #2, 1f
ldr tmp1w, [src], #4
str tmp1w, [dst], #4
1:
tbz count, #1, 1f
ldrh tmp1w, [src], #2
strh tmp1w, [dst], #2
1:
tbz count, #0, 1f
ldrb tmp1w, [src]
strb tmp1w, [dst]
1:
ret
.Lmov_not_short_down:
/* We don't much care about the alignment of DST, but we want SRC
* to be 128-bit (16 byte) aligned so that we don't cross cache line
* boundaries on both loads and stores. */
neg tmp2, src
ands tmp2, tmp2, #15 /* Bytes to reach alignment. */
b.eq 2f
sub count, count, tmp2
/* Move enough data to reach alignment; unlike memcpy, we have to
* be aware of the overlap, which means we can't move data twice. */
tbz tmp2, #3, 1f
ldr tmp1, [src], #8
str tmp1, [dst], #8
1:
tbz tmp2, #2, 1f
ldr tmp1w, [src], #4
str tmp1w, [dst], #4
1:
tbz tmp2, #1, 1f
ldrh tmp1w, [src], #2
strh tmp1w, [dst], #2
1:
tbz tmp2, #0, 1f
ldrb tmp1w, [src], #1
strb tmp1w, [dst], #1
1:
/* There may be less than 63 bytes to go now. */
cmp count, #63
b.le .Ltail63down
2:
subs count, count, #128
b.ge .Lmov_body_large_down
/* Less than 128 bytes to move, so handle 64 here and then jump
* to the tail. */
ldp A_l, A_h, [src]
ldp B_l, B_h, [src, #16]
ldp C_l, C_h, [src, #32]
ldp D_l, D_h, [src, #48]
stp A_l, A_h, [dst]
stp B_l, B_h, [dst, #16]
stp C_l, C_h, [dst, #32]
stp D_l, D_h, [dst, #48]
tst count, #0x3f
add src, src, #64
add dst, dst, #64
b.ne .Ltail63down
ret
/* Critical loop. Start at a new cache line boundary. Assuming
* 64 bytes per line this ensures the entire loop is in one line. */
.p2align 6
.Lmov_body_large_down:
/* There are at least 128 bytes to move. */
ldp A_l, A_h, [src, #0]
sub dst, dst, #16 /* Pre-bias. */
ldp B_l, B_h, [src, #16]
ldp C_l, C_h, [src, #32]
ldp D_l, D_h, [src, #48]! /* src += 64 - Pre-bias. */
1:
stp A_l, A_h, [dst, #16]
ldp A_l, A_h, [src, #16]
stp B_l, B_h, [dst, #32]
ldp B_l, B_h, [src, #32]
stp C_l, C_h, [dst, #48]
ldp C_l, C_h, [src, #48]
stp D_l, D_h, [dst, #64]!
ldp D_l, D_h, [src, #64]!
subs count, count, #64
b.ge 1b
stp A_l, A_h, [dst, #16]
stp B_l, B_h, [dst, #32]
stp C_l, C_h, [dst, #48]
stp D_l, D_h, [dst, #64]
add src, src, #16
add dst, dst, #64 + 16
tst count, #0x3f
b.ne .Ltail63down
ret
END(memmove)

236
libc/arch-arm64/generic/bionic/memset.S Normal file
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@ -0,0 +1,236 @@
/* Copyright (c) 2012, Linaro Limited
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.
* Neither the name of the Linaro nor the
names of its contributors may be used to endorse or promote products
derived from this software without specific prior written permission.
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
HOLDER 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.
*/
/* Assumptions:
*
* ARMv8-a, AArch64
* Unaligned accesses
*
*/
#include <private/bionic_asm.h>
/* By default we assume that the DC instruction can be used to zero
data blocks more efficiently. In some circumstances this might be
unsafe, for example in an asymmetric multiprocessor environment with
different DC clear lengths (neither the upper nor lower lengths are
safe to use). The feature can be disabled by defining DONT_USE_DC.
If code may be run in a virtualized environment, then define
MAYBE_VIRT. This will cause the code to cache the system register
values rather than re-reading them each call. */
#define dstin x0
#define val w1
#define count x2
#define tmp1 x3
#define tmp1w w3
#define tmp2 x4
#define tmp2w w4
#define zva_len_x x5
#define zva_len w5
#define zva_bits_x x6
#define A_l x7
#define A_lw w7
#define dst x8
#define tmp3w w9
ENTRY(memset)
mov dst, dstin /* Preserve return value. */
ands A_lw, val, #255
#ifndef DONT_USE_DC
b.eq .Lzero_mem
#endif
orr A_lw, A_lw, A_lw, lsl #8
orr A_lw, A_lw, A_lw, lsl #16
orr A_l, A_l, A_l, lsl #32
.Ltail_maybe_long:
cmp count, #64
b.ge .Lnot_short
.Ltail_maybe_tiny:
cmp count, #15
b.le .Ltail15tiny
.Ltail63:
ands tmp1, count, #0x30
b.eq .Ltail15
add dst, dst, tmp1
cmp tmp1w, #0x20
b.eq 1f
b.lt 2f
stp A_l, A_l, [dst, #-48]
1:
stp A_l, A_l, [dst, #-32]
2:
stp A_l, A_l, [dst, #-16]
.Ltail15:
and count, count, #15
add dst, dst, count
stp A_l, A_l, [dst, #-16] /* Repeat some/all of last store. */
ret
.Ltail15tiny:
/* Set up to 15 bytes. Does not assume earlier memory
being set. */
tbz count, #3, 1f
str A_l, [dst], #8
1:
tbz count, #2, 1f
str A_lw, [dst], #4
1:
tbz count, #1, 1f
strh A_lw, [dst], #2
1:
tbz count, #0, 1f
strb A_lw, [dst]
1:
ret
/* Critical loop. Start at a new cache line boundary. Assuming
* 64 bytes per line, this ensures the entire loop is in one line. */
.p2align 6
.Lnot_short:
neg tmp2, dst
ands tmp2, tmp2, #15
b.eq 2f
/* Bring DST to 128-bit (16-byte) alignment. We know that there's
* more than that to set, so we simply store 16 bytes and advance by
* the amount required to reach alignment. */
sub count, count, tmp2
stp A_l, A_l, [dst]
add dst, dst, tmp2
/* There may be less than 63 bytes to go now. */
cmp count, #63
b.le .Ltail63
2:
sub dst, dst, #16 /* Pre-bias. */
sub count, count, #64
1:
stp A_l, A_l, [dst, #16]
stp A_l, A_l, [dst, #32]
stp A_l, A_l, [dst, #48]
stp A_l, A_l, [dst, #64]!
subs count, count, #64
b.ge 1b
tst count, #0x3f
add dst, dst, #16
b.ne .Ltail63
ret
#ifndef DONT_USE_DC
/* For zeroing memory, check to see if we can use the ZVA feature to
* zero entire 'cache' lines. */
.Lzero_mem:
mov A_l, #0
cmp count, #63
b.le .Ltail_maybe_tiny
neg tmp2, dst
ands tmp2, tmp2, #15
b.eq 1f
sub count, count, tmp2
stp A_l, A_l, [dst]
add dst, dst, tmp2
cmp count, #63
b.le .Ltail63
1:
/* For zeroing small amounts of memory, it's not worth setting up
* the line-clear code. */
cmp count, #128
b.lt .Lnot_short
#ifdef MAYBE_VIRT
/* For efficiency when virtualized, we cache the ZVA capability. */
adrp tmp2, .Lcache_clear
ldr zva_len, [tmp2, #:lo12:.Lcache_clear]
tbnz zva_len, #31, .Lnot_short
cbnz zva_len, .Lzero_by_line
mrs tmp1, dczid_el0
tbz tmp1, #4, 1f
/* ZVA not available. Remember this for next time. */
mov zva_len, #~0
str zva_len, [tmp2, #:lo12:.Lcache_clear]
b .Lnot_short
1:
mov tmp3w, #4
and zva_len, tmp1w, #15 /* Safety: other bits reserved. */
lsl zva_len, tmp3w, zva_len
str zva_len, [tmp2, #:lo12:.Lcache_clear]
#else
mrs tmp1, dczid_el0
tbnz tmp1, #4, .Lnot_short
mov tmp3w, #4
and zva_len, tmp1w, #15 /* Safety: other bits reserved. */
lsl zva_len, tmp3w, zva_len
#endif
.Lzero_by_line:
/* Compute how far we need to go to become suitably aligned. We're
* already at quad-word alignment. */
cmp count, zva_len_x
b.lt .Lnot_short /* Not enough to reach alignment. */
sub zva_bits_x, zva_len_x, #1
neg tmp2, dst
ands tmp2, tmp2, zva_bits_x
b.eq 1f /* Already aligned. */
/* Not aligned, check that there's enough to copy after alignment. */
sub tmp1, count, tmp2
cmp tmp1, #64
ccmp tmp1, zva_len_x, #8, ge /* NZCV=0b1000 */
b.lt .Lnot_short
/* We know that there's at least 64 bytes to zero and that it's safe
* to overrun by 64 bytes. */
mov count, tmp1
2:
stp A_l, A_l, [dst]
stp A_l, A_l, [dst, #16]
stp A_l, A_l, [dst, #32]
subs tmp2, tmp2, #64
stp A_l, A_l, [dst, #48]
add dst, dst, #64
b.ge 2b
/* We've overrun a bit, so adjust dst downwards. */
add dst, dst, tmp2
1:
sub count, count, zva_len_x
3:
dc zva, dst
add dst, dst, zva_len_x
subs count, count, zva_len_x
b.ge 3b
ands count, count, zva_bits_x
b.ne .Ltail_maybe_long
ret
END(memset)
#ifdef MAYBE_VIRT
.bss
.p2align 2
.Lcache_clear:
.space 4
#endif
#endif /* DONT_USE_DC */

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libc/arch-arm64/generic/bionic/strcmp.S Normal file
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/* Copyright (c) 2012, Linaro Limited
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.
* Neither the name of the Linaro nor the
names of its contributors may be used to endorse or promote products
derived from this software without specific prior written permission.
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
HOLDER 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.
*/
/* Assumptions:
*
* ARMv8-a, AArch64
*/
#include <private/bionic_asm.h>
#define REP8_01 0x0101010101010101
#define REP8_7f 0x7f7f7f7f7f7f7f7f
#define REP8_80 0x8080808080808080
/* Parameters and result. */
#define src1 x0
#define src2 x1
#define result x0
/* Internal variables. */
#define data1 x2
#define data1w w2
#define data2 x3
#define data2w w3
#define has_nul x4
#define diff x5
#define syndrome x6
#define tmp1 x7
#define tmp2 x8
#define tmp3 x9
#define zeroones x10
#define pos x11
/* Start of performance-critical section -- one 64B cache line. */
ENTRY(strcmp)
eor tmp1, src1, src2
mov zeroones, #REP8_01
tst tmp1, #7
b.ne .Lmisaligned8
ands tmp1, src1, #7
b.ne .Lmutual_align
/* NUL detection works on the principle that (X - 1) & (~X) & 0x80
(=> (X - 1) & ~(X | 0x7f)) is non-zero iff a byte is zero, and
can be done in parallel across the entire word. */
.Lloop_aligned:
ldr data1, [src1], #8
ldr data2, [src2], #8
.Lstart_realigned:
sub tmp1, data1, zeroones
orr tmp2, data1, #REP8_7f
eor diff, data1, data2 /* Non-zero if differences found. */
bic has_nul, tmp1, tmp2 /* Non-zero if NUL terminator. */
orr syndrome, diff, has_nul
cbz syndrome, .Lloop_aligned
/* End of performance-critical section -- one 64B cache line. */
#ifndef __AARCH64EB__
rev syndrome, syndrome
rev data1, data1
/* The MS-non-zero bit of the syndrome marks either the first bit
that is different, or the top bit of the first zero byte.
Shifting left now will bring the critical information into the
top bits. */
clz pos, syndrome
rev data2, data2
lsl data1, data1, pos
lsl data2, data2, pos
/* But we need to zero-extend (char is unsigned) the value and then
perform a signed 32-bit subtraction. */
lsr data1, data1, #56
sub result, data1, data2, lsr #56
ret
#else
/* For big-endian we cannot use the trick with the syndrome value
as carry-propagation can corrupt the upper bits if the trailing
bytes in the string contain 0x01. */
/* However, if there is no NUL byte in the dword, we can generate
the result directly. We can't just subtract the bytes as the
MSB might be significant. */
cbnz has_nul, 1f
cmp data1, data2
cset result, ne
cneg result, result, lo
ret
1:
/* Re-compute the NUL-byte detection, using a byte-reversed value. */
rev tmp3, data1
sub tmp1, tmp3, zeroones
orr tmp2, tmp3, #REP8_7f
bic has_nul, tmp1, tmp2
rev has_nul, has_nul
orr syndrome, diff, has_nul
clz pos, syndrome
/* The MS-non-zero bit of the syndrome marks either the first bit
that is different, or the top bit of the first zero byte.
Shifting left now will bring the critical information into the
top bits. */
lsl data1, data1, pos
lsl data2, data2, pos
/* But we need to zero-extend (char is unsigned) the value and then
perform a signed 32-bit subtraction. */
lsr data1, data1, #56
sub result, data1, data2, lsr #56
ret
#endif
.Lmutual_align:
/* Sources are mutually aligned, but are not currently at an
alignment boundary. Round down the addresses and then mask off
the bytes that preceed the start point. */
bic src1, src1, #7
bic src2, src2, #7
lsl tmp1, tmp1, #3 /* Bytes beyond alignment -> bits. */
ldr data1, [src1], #8
neg tmp1, tmp1 /* Bits to alignment -64. */
ldr data2, [src2], #8
mov tmp2, #~0
#ifdef __AARCH64EB__
/* Big-endian. Early bytes are at MSB. */
lsl tmp2, tmp2, tmp1 /* Shift (tmp1 & 63). */
#else
/* Little-endian. Early bytes are at LSB. */
lsr tmp2, tmp2, tmp1 /* Shift (tmp1 & 63). */
#endif
orr data1, data1, tmp2
orr data2, data2, tmp2
b .Lstart_realigned
.Lmisaligned8:
/* We can do better than this. */
ldrb data1w, [src1], #1
ldrb data2w, [src2], #1
cmp data1w, #1
ccmp data1w, data2w, #0, cs /* NZCV = 0b0000. */
b.eq .Lmisaligned8
sub result, data1, data2
ret
END(strcmp)

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libc/arch-arm64/generic/bionic/strlen.S Normal file
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/* Copyright (c) 2014, Linaro Limited
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.
* Neither the name of the Linaro nor the
names of its contributors may be used to endorse or promote products
derived from this software without specific prior written permission.
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
HOLDER 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.
*/
/* Assumptions:
*
* ARMv8-a, AArch64
*/
#include <private/bionic_asm.h>
/* Arguments and results. */
#define srcin x0
#define len x0
/* Locals and temporaries. */
#define src x1
#define data1 x2
#define data2 x3
#define data2a x4
#define has_nul1 x5
#define has_nul2 x6
#define tmp1 x7
#define tmp2 x8
#define tmp3 x9
#define tmp4 x10
#define zeroones x11
#define pos x12
#define REP8_01 0x0101010101010101
#define REP8_7f 0x7f7f7f7f7f7f7f7f
#define REP8_80 0x8080808080808080
/* Start of critial section -- keep to one 64Byte cache line. */
ENTRY(strlen)
mov zeroones, #REP8_01
bic src, srcin, #15
ands tmp1, srcin, #15
b.ne .Lmisaligned
/* NUL detection works on the principle that (X - 1) & (~X) & 0x80
(=> (X - 1) & ~(X | 0x7f)) is non-zero iff a byte is zero, and
can be done in parallel across the entire word. */
/* The inner loop deals with two Dwords at a time. This has a
slightly higher start-up cost, but we should win quite quickly,
especially on cores with a high number of issue slots per
cycle, as we get much better parallelism out of the operations. */
.Lloop:
ldp data1, data2, [src], #16
.Lrealigned:
sub tmp1, data1, zeroones
orr tmp2, data1, #REP8_7f
sub tmp3, data2, zeroones
orr tmp4, data2, #REP8_7f
bic has_nul1, tmp1, tmp2
bics has_nul2, tmp3, tmp4
ccmp has_nul1, #0, #0, eq /* NZCV = 0000 */
b.eq .Lloop
/* End of critical section -- keep to one 64Byte cache line. */
sub len, src, srcin
cbz has_nul1, .Lnul_in_data2
#ifdef __AARCH64EB__
mov data2, data1
#endif
sub len, len, #8
mov has_nul2, has_nul1
.Lnul_in_data2:
#ifdef __AARCH64EB__
/* For big-endian, carry propagation (if the final byte in the
string is 0x01) means we cannot use has_nul directly. The
easiest way to get the correct byte is to byte-swap the data
and calculate the syndrome a second time. */
rev data2, data2
sub tmp1, data2, zeroones
orr tmp2, data2, #REP8_7f
bic has_nul2, tmp1, tmp2
#endif
sub len, len, #8
rev has_nul2, has_nul2
clz pos, has_nul2
add len, len, pos, lsr #3 /* Bits to bytes. */
ret
.Lmisaligned:
cmp tmp1, #8
neg tmp1, tmp1
ldp data1, data2, [src], #16
lsl tmp1, tmp1, #3 /* Bytes beyond alignment -> bits. */
mov tmp2, #~0
#ifdef __AARCH64EB__
/* Big-endian. Early bytes are at MSB. */
lsl tmp2, tmp2, tmp1 /* Shift (tmp1 & 63). */
#else
/* Little-endian. Early bytes are at LSB. */
lsr tmp2, tmp2, tmp1 /* Shift (tmp1 & 63). */
#endif
orr data1, data1, tmp2
orr data2a, data2, tmp2
csinv data1, data1, xzr, le
csel data2, data2, data2a, le
b .Lrealigned
END(strlen)

217
libc/arch-arm64/generic/bionic/strncmp.S Normal file
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/* Copyright (c) 2014, Linaro Limited
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.
* Neither the name of the Linaro nor the
names of its contributors may be used to endorse or promote products
derived from this software without specific prior written permission.
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
HOLDER 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.
*/
/* Assumptions:
*
* ARMv8-a, AArch64
*/
#include <private/bionic_asm.h>
#define REP8_01 0x0101010101010101
#define REP8_7f 0x7f7f7f7f7f7f7f7f
#define REP8_80 0x8080808080808080
/* Parameters and result. */
#define src1 x0
#define src2 x1
#define limit x2
#define result x0
/* Internal variables. */
#define data1 x3
#define data1w w3
#define data2 x4
#define data2w w4
#define has_nul x5
#define diff x6
#define syndrome x7
#define tmp1 x8
#define tmp2 x9
#define tmp3 x10
#define zeroones x11
#define pos x12
#define limit_wd x13
#define mask x14
#define endloop x15
.text
.p2align 6
.rep 7
nop /* Pad so that the loop below fits a cache line. */
.endr
ENTRY(strncmp)
cbz limit, .Lret0
eor tmp1, src1, src2
mov zeroones, #REP8_01
tst tmp1, #7
b.ne .Lmisaligned8
ands tmp1, src1, #7
b.ne .Lmutual_align
/* Calculate the number of full and partial words -1. */
sub limit_wd, limit, #1 /* limit != 0, so no underflow. */
lsr limit_wd, limit_wd, #3 /* Convert to Dwords. */
/* NUL detection works on the principle that (X - 1) & (~X) & 0x80
(=> (X - 1) & ~(X | 0x7f)) is non-zero iff a byte is zero, and
can be done in parallel across the entire word. */
/* Start of performance-critical section -- one 64B cache line. */
.Lloop_aligned:
ldr data1, [src1], #8
ldr data2, [src2], #8
.Lstart_realigned:
subs limit_wd, limit_wd, #1
sub tmp1, data1, zeroones
orr tmp2, data1, #REP8_7f
eor diff, data1, data2 /* Non-zero if differences found. */
csinv endloop, diff, xzr, pl /* Last Dword or differences. */
bics has_nul, tmp1, tmp2 /* Non-zero if NUL terminator. */
ccmp endloop, #0, #0, eq
b.eq .Lloop_aligned
/* End of performance-critical section -- one 64B cache line. */
/* Not reached the limit, must have found the end or a diff. */
tbz limit_wd, #63, .Lnot_limit
/* Limit % 8 == 0 => all bytes significant. */
ands limit, limit, #7
b.eq .Lnot_limit
lsl limit, limit, #3 /* Bits -> bytes. */
mov mask, #~0
#ifdef __AARCH64EB__
lsr mask, mask, limit
#else
lsl mask, mask, limit
#endif
bic data1, data1, mask
bic data2, data2, mask
/* Make sure that the NUL byte is marked in the syndrome. */
orr has_nul, has_nul, mask
.Lnot_limit:
orr syndrome, diff, has_nul
#ifndef __AARCH64EB__
rev syndrome, syndrome
rev data1, data1
/* The MS-non-zero bit of the syndrome marks either the first bit
that is different, or the top bit of the first zero byte.
Shifting left now will bring the critical information into the
top bits. */
clz pos, syndrome
rev data2, data2
lsl data1, data1, pos
lsl data2, data2, pos
/* But we need to zero-extend (char is unsigned) the value and then
perform a signed 32-bit subtraction. */
lsr data1, data1, #56
sub result, data1, data2, lsr #56
ret
#else
/* For big-endian we cannot use the trick with the syndrome value
as carry-propagation can corrupt the upper bits if the trailing
bytes in the string contain 0x01. */
/* However, if there is no NUL byte in the dword, we can generate
the result directly. We can't just subtract the bytes as the
MSB might be significant. */
cbnz has_nul, 1f
cmp data1, data2
cset result, ne
cneg result, result, lo
ret
1:
/* Re-compute the NUL-byte detection, using a byte-reversed value. */
rev tmp3, data1
sub tmp1, tmp3, zeroones
orr tmp2, tmp3, #REP8_7f
bic has_nul, tmp1, tmp2
rev has_nul, has_nul
orr syndrome, diff, has_nul
clz pos, syndrome
/* The MS-non-zero bit of the syndrome marks either the first bit
that is different, or the top bit of the first zero byte.
Shifting left now will bring the critical information into the
top bits. */
lsl data1, data1, pos
lsl data2, data2, pos
/* But we need to zero-extend (char is unsigned) the value and then
perform a signed 32-bit subtraction. */
lsr data1, data1, #56
sub result, data1, data2, lsr #56
ret
#endif
.Lmutual_align:
/* Sources are mutually aligned, but are not currently at an
alignment boundary. Round down the addresses and then mask off
the bytes that precede the start point.
We also need to adjust the limit calculations, but without
overflowing if the limit is near ULONG_MAX. */
bic src1, src1, #7
bic src2, src2, #7
ldr data1, [src1], #8
neg tmp3, tmp1, lsl #3 /* 64 - bits(bytes beyond align). */
ldr data2, [src2], #8
mov tmp2, #~0
sub limit_wd, limit, #1 /* limit != 0, so no underflow. */
#ifdef __AARCH64EB__
/* Big-endian. Early bytes are at MSB. */
lsl tmp2, tmp2, tmp3 /* Shift (tmp1 & 63). */
#else
/* Little-endian. Early bytes are at LSB. */
lsr tmp2, tmp2, tmp3 /* Shift (tmp1 & 63). */
#endif
and tmp3, limit_wd, #7
lsr limit_wd, limit_wd, #3
/* Adjust the limit. Only low 3 bits used, so overflow irrelevant. */
add limit, limit, tmp1
add tmp3, tmp3, tmp1
orr data1, data1, tmp2
orr data2, data2, tmp2
add limit_wd, limit_wd, tmp3, lsr #3
b .Lstart_realigned
.Lret0:
mov result, #0
ret
.p2align 6
.Lmisaligned8:
sub limit, limit, #1
1:
/* Perhaps we can do better than this. */
ldrb data1w, [src1], #1
ldrb data2w, [src2], #1
subs limit, limit, #1
ccmp data1w, #1, #0, cs /* NZCV = 0b0000. */
ccmp data1w, data2w, #0, cs /* NZCV = 0b0000. */
b.eq 1b
sub result, data1, data2
ret
END(strncmp)

174
libc/arch-arm64/generic/bionic/strnlen.S Normal file
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/* Copyright (c) 2014, Linaro Limited
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.
* Neither the name of the Linaro nor the
names of its contributors may be used to endorse or promote products
derived from this software without specific prior written permission.
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
HOLDER 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.
*/
/* Assumptions:
*
* ARMv8-a, AArch64
*/
#include <private/bionic_asm.h>
/* Arguments and results. */
#define srcin x0
#define len x0
#define limit x1
/* Locals and temporaries. */
#define src x2
#define data1 x3
#define data2 x4
#define data2a x5
#define has_nul1 x6
#define has_nul2 x7
#define tmp1 x8
#define tmp2 x9
#define tmp3 x10
#define tmp4 x11
#define zeroones x12
#define pos x13
#define limit_wd x14
#define REP8_01 0x0101010101010101
#define REP8_7f 0x7f7f7f7f7f7f7f7f
#define REP8_80 0x8080808080808080
.text
.p2align 6
.Lstart:
/* Pre-pad to ensure critical loop begins an icache line. */
.rep 7
nop
.endr
/* Put this code here to avoid wasting more space with pre-padding. */
.Lhit_limit:
mov len, limit
ret
ENTRY(strnlen)
cbz limit, .Lhit_limit
mov zeroones, #REP8_01
bic src, srcin, #15
ands tmp1, srcin, #15
b.ne .Lmisaligned
/* Calculate the number of full and partial words -1. */
sub limit_wd, limit, #1 /* Limit != 0, so no underflow. */
lsr limit_wd, limit_wd, #4 /* Convert to Qwords. */
/* NUL detection works on the principle that (X - 1) & (~X) & 0x80
(=> (X - 1) & ~(X | 0x7f)) is non-zero iff a byte is zero, and
can be done in parallel across the entire word. */
/* The inner loop deals with two Dwords at a time. This has a
slightly higher start-up cost, but we should win quite quickly,
especially on cores with a high number of issue slots per
cycle, as we get much better parallelism out of the operations. */
/* Start of critial section -- keep to one 64Byte cache line. */
.Lloop:
ldp data1, data2, [src], #16
.Lrealigned:
sub tmp1, data1, zeroones
orr tmp2, data1, #REP8_7f
sub tmp3, data2, zeroones
orr tmp4, data2, #REP8_7f
bic has_nul1, tmp1, tmp2
bic has_nul2, tmp3, tmp4
subs limit_wd, limit_wd, #1
orr tmp1, has_nul1, has_nul2
ccmp tmp1, #0, #0, pl /* NZCV = 0000 */
b.eq .Lloop
/* End of critical section -- keep to one 64Byte cache line. */
orr tmp1, has_nul1, has_nul2
cbz tmp1, .Lhit_limit /* No null in final Qword. */
/* We know there's a null in the final Qword. The easiest thing
to do now is work out the length of the string and return
MIN (len, limit). */
sub len, src, srcin
cbz has_nul1, .Lnul_in_data2
#ifdef __AARCH64EB__
mov data2, data1
#endif
sub len, len, #8
mov has_nul2, has_nul1
.Lnul_in_data2:
#ifdef __AARCH64EB__
/* For big-endian, carry propagation (if the final byte in the
string is 0x01) means we cannot use has_nul directly. The
easiest way to get the correct byte is to byte-swap the data
and calculate the syndrome a second time. */
rev data2, data2
sub tmp1, data2, zeroones
orr tmp2, data2, #REP8_7f
bic has_nul2, tmp1, tmp2
#endif
sub len, len, #8
rev has_nul2, has_nul2
clz pos, has_nul2
add len, len, pos, lsr #3 /* Bits to bytes. */
cmp len, limit
csel len, len, limit, ls /* Return the lower value. */
ret
.Lmisaligned:
/* Deal with a partial first word.
We're doing two things in parallel here;
1) Calculate the number of words (but avoiding overflow if
limit is near ULONG_MAX) - to do this we need to work out
limit + tmp1 - 1 as a 65-bit value before shifting it;
2) Load and mask the initial data words - we force the bytes
before the ones we are interested in to 0xff - this ensures
early bytes will not hit any zero detection. */
sub limit_wd, limit, #1
neg tmp4, tmp1
cmp tmp1, #8
and tmp3, limit_wd, #15
lsr limit_wd, limit_wd, #4
mov tmp2, #~0
ldp data1, data2, [src], #16
lsl tmp4, tmp4, #3 /* Bytes beyond alignment -> bits. */
add tmp3, tmp3, tmp1
#ifdef __AARCH64EB__
/* Big-endian. Early bytes are at MSB. */
lsl tmp2, tmp2, tmp4 /* Shift (tmp1 & 63). */
#else
/* Little-endian. Early bytes are at LSB. */
lsr tmp2, tmp2, tmp4 /* Shift (tmp1 & 63). */
#endif
add limit_wd, limit_wd, tmp3, lsr #4
orr data1, data1, tmp2
orr data2a, data2, tmp2
csinv data1, data1, xzr, le
csel data2, data2, data2a, le
b .Lrealigned
END(strnlen)

9
libc/arch-arm64/generic/generic.mk Normal file
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libc_bionic_src_files_arm64 += \
arch-arm64/generic/bionic/memcmp.S \
arch-arm64/generic/bionic/memcpy.S \
arch-arm64/generic/bionic/memmove.S \
arch-arm64/generic/bionic/memset.S \
arch-arm64/generic/bionic/strcmp.S \
arch-arm64/generic/bionic/strlen.S \
arch-arm64/generic/bionic/strncmp.S \
arch-arm64/generic/bionic/strnlen.S \