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/* Optimized memset for Fujitsu A64FX processor.
Copyright (C) 2021 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
<https://www.gnu.org/licenses/>. */
#include <sysdep.h>
#include <sysdeps/aarch64/memset-reg.h>
/* Assumptions:
*
* ARMv8.2-a, AArch64, unaligned accesses, sve
*
*/
#define L1_SIZE (64*1024) // L1 64KB
#define L2_SIZE (8*1024*1024) // L2 8MB - 1MB
#define CACHE_LINE_SIZE 256
#define PF_DIST_L1 (CACHE_LINE_SIZE * 16) // Prefetch distance L1
#define ZF_DIST (CACHE_LINE_SIZE * 21) // Zerofill distance
#define rest x8
#define vector_length x9
#define vl_remainder x10 // vector_length remainder
#define cl_remainder x11 // CACHE_LINE_SIZE remainder
#if HAVE_AARCH64_SVE_ASM
# if IS_IN (libc)
# define MEMSET __memset_a64fx
.arch armv8.2-a+sve
.macro dc_zva times
dc zva, tmp1
add tmp1, tmp1, CACHE_LINE_SIZE
.if \times-1
dc_zva "(\times-1)"
.endif
.endm
.macro st1b_unroll first=0, last=7
st1b z0.b, p0, [dst, #\first, mul vl]
.if \last-\first
st1b_unroll "(\first+1)", \last
.endif
.endm
.macro shortcut_for_small_size exit
// if rest <= vector_length * 2
whilelo p0.b, xzr, count
whilelo p1.b, vector_length, count
b.last 1f
st1b z0.b, p0, [dstin, #0, mul vl]
st1b z0.b, p1, [dstin, #1, mul vl]
ret
1: // if rest > vector_length * 8
cmp count, vector_length, lsl 3 // vector_length * 8
b.hi \exit
// if rest <= vector_length * 4
lsl tmp1, vector_length, 1 // vector_length * 2
whilelo p2.b, tmp1, count
incb tmp1
whilelo p3.b, tmp1, count
b.last 1f
st1b z0.b, p0, [dstin, #0, mul vl]
st1b z0.b, p1, [dstin, #1, mul vl]
st1b z0.b, p2, [dstin, #2, mul vl]
st1b z0.b, p3, [dstin, #3, mul vl]
ret
1: // if rest <= vector_length * 8
lsl tmp1, vector_length, 2 // vector_length * 4
whilelo p4.b, tmp1, count
incb tmp1
whilelo p5.b, tmp1, count
b.last 1f
st1b z0.b, p0, [dstin, #0, mul vl]
st1b z0.b, p1, [dstin, #1, mul vl]
st1b z0.b, p2, [dstin, #2, mul vl]
st1b z0.b, p3, [dstin, #3, mul vl]
st1b z0.b, p4, [dstin, #4, mul vl]
st1b z0.b, p5, [dstin, #5, mul vl]
ret
1: lsl tmp1, vector_length, 2 // vector_length * 4
incb tmp1 // vector_length * 5
incb tmp1 // vector_length * 6
whilelo p6.b, tmp1, count
incb tmp1
whilelo p7.b, tmp1, count
st1b z0.b, p0, [dstin, #0, mul vl]
st1b z0.b, p1, [dstin, #1, mul vl]
st1b z0.b, p2, [dstin, #2, mul vl]
st1b z0.b, p3, [dstin, #3, mul vl]
st1b z0.b, p4, [dstin, #4, mul vl]
st1b z0.b, p5, [dstin, #5, mul vl]
st1b z0.b, p6, [dstin, #6, mul vl]
st1b z0.b, p7, [dstin, #7, mul vl]
ret
.endm
ENTRY (MEMSET)
PTR_ARG (0)
SIZE_ARG (2)
cbnz count, 1f
ret
1: dup z0.b, valw
cntb vector_length
// shortcut for less than vector_length * 8
// gives a free ptrue to p0.b for n >= vector_length
shortcut_for_small_size L(vl_agnostic)
// end of shortcut
L(vl_agnostic): // VL Agnostic
mov rest, count
mov dst, dstin
add dstend, dstin, count
// if rest >= L2_SIZE && vector_length == 64 then L(L2)
mov tmp1, 64
cmp rest, L2_SIZE
ccmp vector_length, tmp1, 0, cs
b.eq L(L2)
// if rest >= L1_SIZE && vector_length == 64 then L(L1_prefetch)
cmp rest, L1_SIZE
ccmp vector_length, tmp1, 0, cs
b.eq L(L1_prefetch)
L(unroll32):
lsl tmp1, vector_length, 3 // vector_length * 8
lsl tmp2, vector_length, 5 // vector_length * 32
.p2align 3
1: cmp rest, tmp2
b.cc L(unroll8)
st1b_unroll
add dst, dst, tmp1
st1b_unroll
add dst, dst, tmp1
st1b_unroll
add dst, dst, tmp1
st1b_unroll
add dst, dst, tmp1
sub rest, rest, tmp2
b 1b
L(unroll8):
lsl tmp1, vector_length, 3
.p2align 3
1: cmp rest, tmp1
b.cc L(last)
st1b_unroll
add dst, dst, tmp1
sub rest, rest, tmp1
b 1b
L(last):
whilelo p0.b, xzr, rest
whilelo p1.b, vector_length, rest
b.last 1f
st1b z0.b, p0, [dst, #0, mul vl]
st1b z0.b, p1, [dst, #1, mul vl]
ret
1: lsl tmp1, vector_length, 1 // vector_length * 2
whilelo p2.b, tmp1, rest
incb tmp1
whilelo p3.b, tmp1, rest
b.last 1f
st1b z0.b, p0, [dst, #0, mul vl]
st1b z0.b, p1, [dst, #1, mul vl]
st1b z0.b, p2, [dst, #2, mul vl]
st1b z0.b, p3, [dst, #3, mul vl]
ret
1: lsl tmp1, vector_length, 2 // vector_length * 4
whilelo p4.b, tmp1, rest
incb tmp1
whilelo p5.b, tmp1, rest
incb tmp1
whilelo p6.b, tmp1, rest
incb tmp1
whilelo p7.b, tmp1, rest
st1b z0.b, p0, [dst, #0, mul vl]
st1b z0.b, p1, [dst, #1, mul vl]
st1b z0.b, p2, [dst, #2, mul vl]
st1b z0.b, p3, [dst, #3, mul vl]
st1b z0.b, p4, [dst, #4, mul vl]
st1b z0.b, p5, [dst, #5, mul vl]
st1b z0.b, p6, [dst, #6, mul vl]
st1b z0.b, p7, [dst, #7, mul vl]
ret
L(L1_prefetch): // if rest >= L1_SIZE
.p2align 3
1: st1b_unroll 0, 3
prfm pstl1keep, [dst, PF_DIST_L1]
st1b_unroll 4, 7
prfm pstl1keep, [dst, PF_DIST_L1 + CACHE_LINE_SIZE]
add dst, dst, CACHE_LINE_SIZE * 2
sub rest, rest, CACHE_LINE_SIZE * 2
cmp rest, L1_SIZE
b.ge 1b
cbnz rest, L(unroll32)
ret
L(L2):
// align dst address at vector_length byte boundary
sub tmp1, vector_length, 1
ands tmp2, dst, tmp1
// if vl_remainder == 0
b.eq 1f
sub vl_remainder, vector_length, tmp2
// process remainder until the first vector_length boundary
whilelt p2.b, xzr, vl_remainder
st1b z0.b, p2, [dst]
add dst, dst, vl_remainder
sub rest, rest, vl_remainder
// align dstin address at CACHE_LINE_SIZE byte boundary
1: mov tmp1, CACHE_LINE_SIZE
ands tmp2, dst, CACHE_LINE_SIZE - 1
// if cl_remainder == 0
b.eq L(L2_dc_zva)
sub cl_remainder, tmp1, tmp2
// process remainder until the first CACHE_LINE_SIZE boundary
mov tmp1, xzr // index
2: whilelt p2.b, tmp1, cl_remainder
st1b z0.b, p2, [dst, tmp1]
incb tmp1
cmp tmp1, cl_remainder
b.lo 2b
add dst, dst, cl_remainder
sub rest, rest, cl_remainder
L(L2_dc_zva):
// zero fill
mov tmp1, dst
dc_zva (ZF_DIST / CACHE_LINE_SIZE) - 1
mov zva_len, ZF_DIST
add tmp1, zva_len, CACHE_LINE_SIZE * 2
// unroll
.p2align 3
1: st1b_unroll 0, 3
add tmp2, dst, zva_len
dc zva, tmp2
st1b_unroll 4, 7
add tmp2, tmp2, CACHE_LINE_SIZE
dc zva, tmp2
add dst, dst, CACHE_LINE_SIZE * 2
sub rest, rest, CACHE_LINE_SIZE * 2
cmp rest, tmp1 // ZF_DIST + CACHE_LINE_SIZE * 2
b.ge 1b
cbnz rest, L(unroll8)
ret
END (MEMSET)
libc_hidden_builtin_def (MEMSET)
#endif /* IS_IN (libc) */
#endif /* HAVE_AARCH64_SVE_ASM */
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