mirror of
git://sourceware.org/git/glibc.git
synced 2024-11-27 03:41:23 +08:00
177 lines
4.1 KiB
ArmAsm
177 lines
4.1 KiB
ArmAsm
/* Copyright (C) 2012-2016 Free Software Foundation, Inc.
|
|
|
|
This file is part of the GNU C Library.
|
|
|
|
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/>. */
|
|
|
|
/* Assumptions:
|
|
*
|
|
* ARMv8-a, AArch64
|
|
* Unaligned accesses
|
|
*
|
|
*/
|
|
|
|
#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
|
|
|
|
#include <sysdep.h>
|
|
|
|
ENTRY_ALIGN (memcpy, 6)
|
|
|
|
mov dst, dstin
|
|
cmp count, #64
|
|
b.ge L(cpy_not_short)
|
|
cmp count, #15
|
|
b.le L(tail15tiny)
|
|
|
|
/* Deal with small copies quickly by dropping straight into the
|
|
* exit block. */
|
|
L(tail63):
|
|
/* 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 L(tail15)
|
|
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]
|
|
|
|
L(tail15):
|
|
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
|
|
|
|
L(tail15tiny):
|
|
/* 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
|
|
|
|
L(cpy_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 L(tail63)
|
|
2:
|
|
subs count, count, #128
|
|
b.ge L(cpy_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 L(tail63)
|
|
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
|
|
L(cpy_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 L(tail63)
|
|
RET
|
|
END (memcpy)
|
|
libc_hidden_builtin_def (memcpy)
|