// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build s390x,go1.11,!gccgo,!appengine
#include "textflag.h"
// Implementation of Poly1305 using the vector facility (vx).
// constants
#define MOD26 V0
#define EX0 V1
#define EX1 V2
#define EX2 V3
// temporaries
#define T_0 V4
#define T_1 V5
#define T_2 V6
#define T_3 V7
#define T_4 V8
// key (r)
#define R_0 V9
#define R_1 V10
#define R_2 V11
#define R_3 V12
#define R_4 V13
#define R5_1 V14
#define R5_2 V15
#define R5_3 V16
#define R5_4 V17
#define RSAVE_0 R5
#define RSAVE_1 R6
#define RSAVE_2 R7
#define RSAVE_3 R8
#define RSAVE_4 R9
#define R5SAVE_1 V28
#define R5SAVE_2 V29
#define R5SAVE_3 V30
#define R5SAVE_4 V31
// message block
#define F_0 V18
#define F_1 V19
#define F_2 V20
#define F_3 V21
#define F_4 V22
// accumulator
#define H_0 V23
#define H_1 V24
#define H_2 V25
#define H_3 V26
#define H_4 V27
GLOBL ·keyMask<>(SB), RODATA, $16
DATA ·keyMask<>+0(SB)/8, $0xffffff0ffcffff0f
DATA ·keyMask<>+8(SB)/8, $0xfcffff0ffcffff0f
GLOBL ·bswapMask<>(SB), RODATA, $16
DATA ·bswapMask<>+0(SB)/8, $0x0f0e0d0c0b0a0908
DATA ·bswapMask<>+8(SB)/8, $0x0706050403020100
GLOBL ·constants<>(SB), RODATA, $64
// MOD26
DATA ·constants<>+0(SB)/8, $0x3ffffff
DATA ·constants<>+8(SB)/8, $0x3ffffff
// EX0
DATA ·constants<>+16(SB)/8, $0x0006050403020100
DATA ·constants<>+24(SB)/8, $0x1016151413121110
// EX1
DATA ·constants<>+32(SB)/8, $0x060c0b0a09080706
DATA ·constants<>+40(SB)/8, $0x161c1b1a19181716
// EX2
DATA ·constants<>+48(SB)/8, $0x0d0d0d0d0d0f0e0d
DATA ·constants<>+56(SB)/8, $0x1d1d1d1d1d1f1e1d
// h = (f*g) % (2**130-5) [partial reduction]
#define MULTIPLY(f0, f1, f2, f3, f4, g0, g1, g2, g3, g4, g51, g52, g53, g54, h0, h1, h2, h3, h4) \
VMLOF f0, g0, h0 \
VMLOF f0, g1, h1 \
VMLOF f0, g2, h2 \
VMLOF f0, g3, h3 \
VMLOF f0, g4, h4 \
VMLOF f1, g54, T_0 \
VMLOF f1, g0, T_1 \
VMLOF f1, g1, T_2 \
VMLOF f1, g2, T_3 \
VMLOF f1, g3, T_4 \
VMALOF f2, g53, h0, h0 \
VMALOF f2, g54, h1, h1 \
VMALOF f2, g0, h2, h2 \
VMALOF f2, g1, h3, h3 \
VMALOF f2, g2, h4, h4 \
VMALOF f3, g52, T_0, T_0 \
VMALOF f3, g53, T_1, T_1 \
VMALOF f3, g54, T_2, T_2 \
VMALOF f3, g0, T_3, T_3 \
VMALOF f3, g1, T_4, T_4 \
VMALOF f4, g51, h0, h0 \
VMALOF f4, g52, h1, h1 \
VMALOF f4, g53, h2, h2 \
VMALOF f4, g54, h3, h3 \
VMALOF f4, g0, h4, h4 \
VAG T_0, h0, h0 \
VAG T_1, h1, h1 \
VAG T_2, h2, h2 \
VAG T_3, h3, h3 \
VAG T_4, h4, h4
// carry h0->h1 h3->h4, h1->h2 h4->h0, h0->h1 h2->h3, h3->h4
#define REDUCE(h0, h1, h2, h3, h4) \
VESRLG $26, h0, T_0 \
VESRLG $26, h3, T_1 \
VN MOD26, h0, h0 \
VN MOD26, h3, h3 \
VAG T_0, h1, h1 \
VAG T_1, h4, h4 \
VESRLG $26, h1, T_2 \
VESRLG $26, h4, T_3 \
VN MOD26, h1, h1 \
VN MOD26, h4, h4 \
VESLG $2, T_3, T_4 \
VAG T_3, T_4, T_4 \
VAG T_2, h2, h2 \
VAG T_4, h0, h0 \
VESRLG $26, h2, T_0 \
VESRLG $26, h0, T_1 \
VN MOD26, h2, h2 \
VN MOD26, h0, h0 \
VAG T_0, h3, h3 \
VAG T_1, h1, h1 \
VESRLG $26, h3, T_2 \
VN MOD26, h3, h3 \
VAG T_2, h4, h4
// expand in0 into d[0] and in1 into d[1]
#define EXPAND(in0, in1, d0, d1, d2, d3, d4) \
VGBM $0x0707, d1 \ // d1=tmp
VPERM in0, in1, EX2, d4 \
VPERM in0, in1, EX0, d0 \
VPERM in0, in1, EX1, d2 \
VN d1, d4, d4 \
VESRLG $26, d0, d1 \
VESRLG $30, d2, d3 \
VESRLG $4, d2, d2 \
VN MOD26, d0, d0 \
VN MOD26, d1, d1 \
VN MOD26, d2, d2 \
VN MOD26, d3, d3
// pack h4:h0 into h1:h0 (no carry)
#define PACK(h0, h1, h2, h3, h4) \
VESLG $26, h1, h1 \
VESLG $26, h3, h3 \
VO h0, h1, h0 \
VO h2, h3, h2 \
VESLG $4, h2, h2 \
VLEIB $7, $48, h1 \
VSLB h1, h2, h2 \
VO h0, h2, h0 \
VLEIB $7, $104, h1 \
VSLB h1, h4, h3 \
VO h3, h0, h0 \
VLEIB $7, $24, h1 \
VSRLB h1, h4, h1
// if h > 2**130-5 then h -= 2**130-5
#define MOD(h0, h1, t0, t1, t2) \
VZERO t0 \
VLEIG $1, $5, t0 \
VACCQ h0, t0, t1 \
VAQ h0, t0, t0 \
VONE t2 \
VLEIG $1, $-4, t2 \
VAQ t2, t1, t1 \
VACCQ h1, t1, t1 \
VONE t2 \
VAQ t2, t1, t1 \
VN h0, t1, t2 \
VNC t0, t1, t1 \
VO t1, t2, h0
// func poly1305vx(out *[16]byte, m *byte, mlen uint64, key *[32]key)
TEXT ·poly1305vx(SB), $0-32
// This code processes up to 2 blocks (32 bytes) per iteration
// using the algorithm described in:
// NEON crypto, Daniel J. Bernstein & Peter Schwabe
// https://cryptojedi.org/papers/neoncrypto-20120320.pdf
LMG out+0(FP), R1, R4 // R1=out, R2=m, R3=mlen, R4=key
// load MOD26, EX0, EX1 and EX2
MOVD $·constants<>(SB), R5
VLM (R5), MOD26, EX2
// setup r
VL (R4), T_0
MOVD $·keyMask<>(SB), R6
VL (R6), T_1
VN T_0, T_1, T_0
EXPAND(T_0, T_0, R_0, R_1, R_2, R_3, R_4)
// setup r*5
VLEIG $0, $5, T_0
VLEIG $1, $5, T_0
// store r (for final block)
VMLOF T_0, R_1, R5SAVE_1
VMLOF T_0, R_2, R5SAVE_2
VMLOF T_0, R_3, R5SAVE_3
VMLOF T_0, R_4, R5SAVE_4
VLGVG $0, R_0, RSAVE_0
VLGVG $0, R_1, RSAVE_1
VLGVG $0, R_2, RSAVE_2
VLGVG $0, R_3, RSAVE_3
VLGVG $0, R_4, RSAVE_4
// skip r**2 calculation
CMPBLE R3, $16, skip
// calculate r**2
MULTIPLY(R_0, R_1, R_2, R_3, R_4, R_0, R_1, R_2, R_3, R_4, R5SAVE_1, R5SAVE_2, R5SAVE_3, R5SAVE_4, H_0, H_1, H_2, H_3, H_4)
REDUCE(H_0, H_1, H_2, H_3, H_4)
VLEIG $0, $5, T_0
VLEIG $1, $5, T_0
VMLOF T_0, H_1, R5_1
VMLOF T_0, H_2, R5_2
VMLOF T_0, H_3, R5_3
VMLOF T_0, H_4, R5_4
VLR H_0, R_0
VLR H_1, R_1
VLR H_2, R_2
VLR H_3, R_3
VLR H_4, R_4
// initialize h
VZERO H_0
VZERO H_1
VZERO H_2
VZERO H_3
VZERO H_4
loop:
CMPBLE R3, $32, b2
VLM (R2), T_0, T_1
SUB $32, R3
MOVD $32(R2), R2
EXPAND(T_0, T_1, F_0, F_1, F_2, F_3, F_4)
VLEIB $4, $1, F_4
VLEIB $12, $1, F_4
multiply:
VAG H_0, F_0, F_0
VAG H_1, F_1, F_1
VAG H_2, F_2, F_2
VAG H_3, F_3, F_3
VAG H_4, F_4, F_4
MULTIPLY(F_0, F_1, F_2, F_3, F_4, R_0, R_1, R_2, R_3, R_4, R5_1, R5_2, R5_3, R5_4, H_0, H_1, H_2, H_3, H_4)
REDUCE(H_0, H_1, H_2, H_3, H_4)
CMPBNE R3, $0, loop
finish:
// sum vectors
VZERO T_0
VSUMQG H_0, T_0, H_0
VSUMQG H_1, T_0, H_1
VSUMQG H_2, T_0, H_2
VSUMQG H_3, T_0, H_3
VSUMQG H_4, T_0, H_4
// h may be >= 2*(2**130-5) so we need to reduce it again
REDUCE(H_0, H_1, H_2, H_3, H_4)
// carry h1->h4
VESRLG $26, H_1, T_1
VN MOD26, H_1, H_1
VAQ T_1, H_2, H_2
VESRLG $26, H_2, T_2
VN MOD26, H_2, H_2
VAQ T_2, H_3, H_3
VESRLG $26, H_3, T_3
VN MOD26, H_3, H_3
VAQ T_3, H_4, H_4
// h is now < 2*(2**130-5)
// pack h into h1 (hi) and h0 (lo)
PACK(H_0, H_1, H_2, H_3, H_4)
// if h > 2**130-5 then h -= 2**130-5
MOD(H_0, H_1, T_0, T_1, T_2)
// h += s
MOVD $·bswapMask<>(SB), R5
VL (R5), T_1
VL 16(R4), T_0
VPERM T_0, T_0, T_1, T_0 // reverse bytes (to big)
VAQ T_0, H_0, H_0
VPERM H_0, H_0, T_1, H_0 // reverse bytes (to little)
VST H_0, (R1)
RET
b2:
CMPBLE R3, $16, b1
// 2 blocks remaining
SUB $17, R3
VL (R2), T_0
VLL R3, 16(R2), T_1
ADD $1, R3
MOVBZ $1, R0
CMPBEQ R3, $16, 2(PC)
VLVGB R3, R0, T_1
EXPAND(T_0, T_1, F_0, F_1, F_2, F_3, F_4)
CMPBNE R3, $16, 2(PC)
VLEIB $12, $1, F_4
VLEIB $4, $1, F_4
// setup [r²,r]
VLVGG $1, RSAVE_0, R_0
VLVGG $1, RSAVE_1, R_1
VLVGG $1, RSAVE_2, R_2
VLVGG $1, RSAVE_3, R_3
VLVGG $1, RSAVE_4, R_4
VPDI $0, R5_1, R5SAVE_1, R5_1
VPDI $0, R5_2, R5SAVE_2, R5_2
VPDI $0, R5_3, R5SAVE_3, R5_3
VPDI $0, R5_4, R5SAVE_4, R5_4
MOVD $0, R3
BR multiply
skip:
VZERO H_0
VZERO H_1
VZERO H_2
VZERO H_3
VZERO H_4
CMPBEQ R3, $0, finish
b1:
// 1 block remaining
SUB $1, R3
VLL R3, (R2), T_0
ADD $1, R3
MOVBZ $1, R0
CMPBEQ R3, $16, 2(PC)
VLVGB R3, R0, T_0
VZERO T_1
EXPAND(T_0, T_1, F_0, F_1, F_2, F_3, F_4)
CMPBNE R3, $16, 2(PC)
VLEIB $4, $1, F_4
VLEIG $1, $1, R_0
VZERO R_1
VZERO R_2
VZERO R_3
VZERO R_4
VZERO R5_1
VZERO R5_2
VZERO R5_3
VZERO R5_4
// setup [r, 1]
VLVGG $0, RSAVE_0, R_0
VLVGG $0, RSAVE_1, R_1
VLVGG $0, RSAVE_2, R_2
VLVGG $0, RSAVE_3, R_3
VLVGG $0, RSAVE_4, R_4
VPDI $0, R5SAVE_1, R5_1, R5_1
VPDI $0, R5SAVE_2, R5_2, R5_2
VPDI $0, R5SAVE_3, R5_3, R5_3
VPDI $0, R5SAVE_4, R5_4, R5_4
MOVD $0, R3
BR multiply
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