platform_bionic/libc/arch-arm64/generic/bionic/memmove.S
Jake Weinstein 2926f9a31e libc: remove bcopy from memmove on 64-bit architectures
* bcopy is deprecated on LP64 by the following commit:

  ce9ce28e5d

Change-Id: I6849916f0ec4a2d0db9a360999ad1dc8edda952b
2015-08-17 22:06:12 +00:00

329 lines
8.3 KiB
ArmAsm

/* 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
* wchar_t is 4 bytes
*/
#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
#if defined(WMEMMOVE)
ENTRY(wmemmove)
lsl count, count, #2
#else
ENTRY(memmove)
#endif
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
#if defined(WMEMMOVE)
END(wmemmove)
#else
END(memmove)
#endif