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/* Copyright (C) 2012-2017 Free Software Foundation, Inc.
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/>. */
#include <sysdep.h>
/* Assumptions:
*
* ARMv8-a, AArch64, unaligned accesses
*
*/
#define dstin x0
#define val x1
#define valw w1
#define count x2
#define dst x3
#define dstend x4
#define tmp1 x5
#define tmp1w w5
#define tmp2 x6
#define tmp2w w6
#define zva_len x7
#define zva_lenw w7
ENTRY_ALIGN (memset, 6)
dup v0.16B, valw
add dstend, dstin, count
cmp count, 96
b.hi L(set_long)
cmp count, 16
b.hs L(set_medium)
mov val, v0.D[0]
/* Set 0..15 bytes. */
tbz count, 3, 1f
str val, [dstin]
str val, [dstend, -8]
ret
nop
1: tbz count, 2, 2f
str valw, [dstin]
str valw, [dstend, -4]
ret
2: cbz count, 3f
strb valw, [dstin]
tbz count, 1, 3f
strh valw, [dstend, -2]
3: ret
/* Set 17..96 bytes. */
L(set_medium):
str q0, [dstin]
tbnz count, 6, L(set96)
str q0, [dstend, -16]
tbz count, 5, 1f
str q0, [dstin, 16]
str q0, [dstend, -32]
1: ret
.p2align 4
/* Set 64..96 bytes. Write 64 bytes from the start and
32 bytes from the end. */
L(set96):
str q0, [dstin, 16]
stp q0, q0, [dstin, 32]
stp q0, q0, [dstend, -32]
ret
.p2align 3
nop
L(set_long):
and valw, valw, 255
bic dst, dstin, 15
str q0, [dstin]
cmp count, 256
ccmp valw, 0, 0, cs
b.eq L(try_zva)
L(no_zva):
sub count, dstend, dst /* Count is 16 too large. */
add dst, dst, 16
sub count, count, 64 + 16 /* Adjust count and bias for loop. */
1: stp q0, q0, [dst], 64
stp q0, q0, [dst, -32]
L(tail64):
subs count, count, 64
b.hi 1b
2: stp q0, q0, [dstend, -64]
stp q0, q0, [dstend, -32]
ret
.p2align 3
L(try_zva):
mrs tmp1, dczid_el0
tbnz tmp1w, 4, L(no_zva)
and tmp1w, tmp1w, 15
cmp tmp1w, 4 /* ZVA size is 64 bytes. */
b.ne L(zva_128)
/* Write the first and last 64 byte aligned block using stp rather
than using DC ZVA. This is faster on some cores.
*/
L(zva_64):
str q0, [dst, 16]
stp q0, q0, [dst, 32]
bic dst, dst, 63
stp q0, q0, [dst, 64]
stp q0, q0, [dst, 96]
sub count, dstend, dst /* Count is now 128 too large. */
sub count, count, 128+64+64 /* Adjust count and bias for loop. */
add dst, dst, 128
nop
1: dc zva, dst
add dst, dst, 64
subs count, count, 64
b.hi 1b
stp q0, q0, [dst, 0]
stp q0, q0, [dst, 32]
stp q0, q0, [dstend, -64]
stp q0, q0, [dstend, -32]
ret
.p2align 3
L(zva_128):
cmp tmp1w, 5 /* ZVA size is 128 bytes. */
b.ne L(zva_other)
str q0, [dst, 16]
stp q0, q0, [dst, 32]
stp q0, q0, [dst, 64]
stp q0, q0, [dst, 96]
bic dst, dst, 127
sub count, dstend, dst /* Count is now 128 too large. */
sub count, count, 128+128 /* Adjust count and bias for loop. */
add dst, dst, 128
1: dc zva, dst
add dst, dst, 128
subs count, count, 128
b.hi 1b
stp q0, q0, [dstend, -128]
stp q0, q0, [dstend, -96]
stp q0, q0, [dstend, -64]
stp q0, q0, [dstend, -32]
ret
L(zva_other):
mov tmp2w, 4
lsl zva_lenw, tmp2w, tmp1w
add tmp1, zva_len, 64 /* Max alignment bytes written. */
cmp count, tmp1
blo L(no_zva)
sub tmp2, zva_len, 1
add tmp1, dst, zva_len
add dst, dst, 16
subs count, tmp1, dst /* Actual alignment bytes to write. */
bic tmp1, tmp1, tmp2 /* Aligned dc zva start address. */
beq 2f
1: stp q0, q0, [dst], 64
stp q0, q0, [dst, -32]
subs count, count, 64
b.hi 1b
2: mov dst, tmp1
sub count, dstend, tmp1 /* Remaining bytes to write. */
subs count, count, zva_len
b.lo 4f
3: dc zva, dst
add dst, dst, zva_len
subs count, count, zva_len
b.hs 3b
4: add count, count, zva_len
b L(tail64)
END (memset)
libc_hidden_def (memset)
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