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/* SPDX-License-Identifier: GPL-2.0 */
/*
* NH - ε-almost-universal hash function, ARM64 NEON accelerated version
*
* Copyright 2018 Google LLC
*
* Author: Eric Biggers <ebiggers@google.com>
*/
#include <linux/linkage.h>
#include <linux/cfi_types.h>
KEY .req x0
MESSAGE .req x1
MESSAGE_LEN .req x2
HASH .req x3
PASS0_SUMS .req v0
PASS1_SUMS .req v1
PASS2_SUMS .req v2
PASS3_SUMS .req v3
K0 .req v4
K1 .req v5
K2 .req v6
K3 .req v7
T0 .req v8
T1 .req v9
T2 .req v10
T3 .req v11
T4 .req v12
T5 .req v13
T6 .req v14
T7 .req v15
.macro _nh_stride k0, k1, k2, k3
// Load next message stride
ld1 {T3.16b}, [MESSAGE], #16
// Load next key stride
ld1 {\k3\().4s}, [KEY], #16
// Add message words to key words
add T0.4s, T3.4s, \k0\().4s
add T1.4s, T3.4s, \k1\().4s
add T2.4s, T3.4s, \k2\().4s
add T3.4s, T3.4s, \k3\().4s
// Multiply 32x32 => 64 and accumulate
mov T4.d[0], T0.d[1]
mov T5.d[0], T1.d[1]
mov T6.d[0], T2.d[1]
mov T7.d[0], T3.d[1]
umlal PASS0_SUMS.2d, T0.2s, T4.2s
umlal PASS1_SUMS.2d, T1.2s, T5.2s
umlal PASS2_SUMS.2d, T2.2s, T6.2s
umlal PASS3_SUMS.2d, T3.2s, T7.2s
.endm
/*
* void nh_neon(const u32 *key, const u8 *message, size_t message_len,
* __le64 hash[NH_NUM_PASSES])
*
* It's guaranteed that message_len % 16 == 0.
*/
SYM_TYPED_FUNC_START(nh_neon)
ld1 {K0.4s,K1.4s}, [KEY], #32
movi PASS0_SUMS.2d, #0
movi PASS1_SUMS.2d, #0
ld1 {K2.4s}, [KEY], #16
movi PASS2_SUMS.2d, #0
movi PASS3_SUMS.2d, #0
subs MESSAGE_LEN, MESSAGE_LEN, #64
blt .Lloop4_done
.Lloop4:
_nh_stride K0, K1, K2, K3
_nh_stride K1, K2, K3, K0
_nh_stride K2, K3, K0, K1
_nh_stride K3, K0, K1, K2
subs MESSAGE_LEN, MESSAGE_LEN, #64
bge .Lloop4
.Lloop4_done:
ands MESSAGE_LEN, MESSAGE_LEN, #63
beq .Ldone
_nh_stride K0, K1, K2, K3
subs MESSAGE_LEN, MESSAGE_LEN, #16
beq .Ldone
_nh_stride K1, K2, K3, K0
subs MESSAGE_LEN, MESSAGE_LEN, #16
beq .Ldone
_nh_stride K2, K3, K0, K1
.Ldone:
// Sum the accumulators for each pass, then store the sums to 'hash'
addp T0.2d, PASS0_SUMS.2d, PASS1_SUMS.2d
addp T1.2d, PASS2_SUMS.2d, PASS3_SUMS.2d
st1 {T0.16b,T1.16b}, [HASH]
ret
SYM_FUNC_END(nh_neon)
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