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/* SPDX-License-Identifier: GPL-2.0 */
/*
* NH - ε-almost-universal hash function, x86_64 SSE2 accelerated
*
* Copyright 2018 Google LLC
*
* Author: Eric Biggers <ebiggers@google.com>
*/
#include <linux/linkage.h>
#define PASS0_SUMS %xmm0
#define PASS1_SUMS %xmm1
#define PASS2_SUMS %xmm2
#define PASS3_SUMS %xmm3
#define K0 %xmm4
#define K1 %xmm5
#define K2 %xmm6
#define K3 %xmm7
#define T0 %xmm8
#define T1 %xmm9
#define T2 %xmm10
#define T3 %xmm11
#define T4 %xmm12
#define T5 %xmm13
#define T6 %xmm14
#define T7 %xmm15
#define KEY %rdi
#define MESSAGE %rsi
#define MESSAGE_LEN %rdx
#define HASH %rcx
.macro _nh_stride k0, k1, k2, k3, offset
// Load next message stride
movdqu \offset(MESSAGE), T1
// Load next key stride
movdqu \offset(KEY), \k3
// Add message words to key words
movdqa T1, T2
movdqa T1, T3
paddd T1, \k0 // reuse k0 to avoid a move
paddd \k1, T1
paddd \k2, T2
paddd \k3, T3
// Multiply 32x32 => 64 and accumulate
pshufd $0x10, \k0, T4
pshufd $0x32, \k0, \k0
pshufd $0x10, T1, T5
pshufd $0x32, T1, T1
pshufd $0x10, T2, T6
pshufd $0x32, T2, T2
pshufd $0x10, T3, T7
pshufd $0x32, T3, T3
pmuludq T4, \k0
pmuludq T5, T1
pmuludq T6, T2
pmuludq T7, T3
paddq \k0, PASS0_SUMS
paddq T1, PASS1_SUMS
paddq T2, PASS2_SUMS
paddq T3, PASS3_SUMS
.endm
/*
* void nh_sse2(const u32 *key, const u8 *message, size_t message_len,
* u8 hash[NH_HASH_BYTES])
*
* It's guaranteed that message_len % 16 == 0.
*/
SYM_FUNC_START(nh_sse2)
movdqu 0x00(KEY), K0
movdqu 0x10(KEY), K1
movdqu 0x20(KEY), K2
add $0x30, KEY
pxor PASS0_SUMS, PASS0_SUMS
pxor PASS1_SUMS, PASS1_SUMS
pxor PASS2_SUMS, PASS2_SUMS
pxor PASS3_SUMS, PASS3_SUMS
sub $0x40, MESSAGE_LEN
jl .Lloop4_done
.Lloop4:
_nh_stride K0, K1, K2, K3, 0x00
_nh_stride K1, K2, K3, K0, 0x10
_nh_stride K2, K3, K0, K1, 0x20
_nh_stride K3, K0, K1, K2, 0x30
add $0x40, KEY
add $0x40, MESSAGE
sub $0x40, MESSAGE_LEN
jge .Lloop4
.Lloop4_done:
and $0x3f, MESSAGE_LEN
jz .Ldone
_nh_stride K0, K1, K2, K3, 0x00
sub $0x10, MESSAGE_LEN
jz .Ldone
_nh_stride K1, K2, K3, K0, 0x10
sub $0x10, MESSAGE_LEN
jz .Ldone
_nh_stride K2, K3, K0, K1, 0x20
.Ldone:
// Sum the accumulators for each pass, then store the sums to 'hash'
movdqa PASS0_SUMS, T0
movdqa PASS2_SUMS, T1
punpcklqdq PASS1_SUMS, T0 // => (PASS0_SUM_A PASS1_SUM_A)
punpcklqdq PASS3_SUMS, T1 // => (PASS2_SUM_A PASS3_SUM_A)
punpckhqdq PASS1_SUMS, PASS0_SUMS // => (PASS0_SUM_B PASS1_SUM_B)
punpckhqdq PASS3_SUMS, PASS2_SUMS // => (PASS2_SUM_B PASS3_SUM_B)
paddq PASS0_SUMS, T0
paddq PASS2_SUMS, T1
movdqu T0, 0x00(HASH)
movdqu T1, 0x10(HASH)
ret
SYM_FUNC_END(nh_sse2)