1// Copyright (c) 2020 The Go Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style 3// license that can be found in the LICENSE file. 4 5// +build arm64,gc,!purego 6 7#include "textflag.h" 8 9// carryPropagate works exactly like carryPropagateGeneric and uses the 10// same AND, ADD, and LSR+MADD instructions emitted by the compiler, but 11// avoids loading R0-R4 twice and uses LDP and STP. 12// 13// See https://golang.org/issues/43145 for the main compiler issue. 14// 15// func carryPropagate(v *Element) 16TEXT ·carryPropagate(SB),NOFRAME|NOSPLIT,$0-8 17 MOVD v+0(FP), R20 18 19 LDP 0(R20), (R0, R1) 20 LDP 16(R20), (R2, R3) 21 MOVD 32(R20), R4 22 23 AND $0x7ffffffffffff, R0, R10 24 AND $0x7ffffffffffff, R1, R11 25 AND $0x7ffffffffffff, R2, R12 26 AND $0x7ffffffffffff, R3, R13 27 AND $0x7ffffffffffff, R4, R14 28 29 ADD R0>>51, R11, R11 30 ADD R1>>51, R12, R12 31 ADD R2>>51, R13, R13 32 ADD R3>>51, R14, R14 33 // R4>>51 * 19 + R10 -> R10 34 LSR $51, R4, R21 35 MOVD $19, R22 36 MADD R22, R10, R21, R10 37 38 STP (R10, R11), 0(R20) 39 STP (R12, R13), 16(R20) 40 MOVD R14, 32(R20) 41 42 RET 43