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// Copyright ©2015 The Gonum Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//
// Some of the loop unrolling code is copied from:
// http://golang.org/src/math/big/arith_amd64.s
// which is distributed under these terms:
//
// Copyright (c) 2012 The Go Authors. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// +build !noasm,!gccgo,!safe
#include "textflag.h"
// func DdotUnitary(x, y []float64) (sum float64)
// This function assumes len(y) >= len(x).
TEXT ·DotUnitary(SB), NOSPLIT, $0
MOVQ x+0(FP), R8
MOVQ x_len+8(FP), DI // n = len(x)
MOVQ y+24(FP), R9
MOVSD $(0.0), X7 // sum = 0
MOVSD $(0.0), X8 // sum = 0
MOVQ $0, SI // i = 0
SUBQ $4, DI // n -= 4
JL tail_uni // if n < 0 goto tail_uni
loop_uni:
// sum += x[i] * y[i] unrolled 4x.
MOVUPD 0(R8)(SI*8), X0
MOVUPD 0(R9)(SI*8), X1
MOVUPD 16(R8)(SI*8), X2
MOVUPD 16(R9)(SI*8), X3
MULPD X1, X0
MULPD X3, X2
ADDPD X0, X7
ADDPD X2, X8
ADDQ $4, SI // i += 4
SUBQ $4, DI // n -= 4
JGE loop_uni // if n >= 0 goto loop_uni
tail_uni:
ADDQ $4, DI // n += 4
JLE end_uni // if n <= 0 goto end_uni
onemore_uni:
// sum += x[i] * y[i] for the remaining 1-3 elements.
MOVSD 0(R8)(SI*8), X0
MOVSD 0(R9)(SI*8), X1
MULSD X1, X0
ADDSD X0, X7
ADDQ $1, SI // i++
SUBQ $1, DI // n--
JNZ onemore_uni // if n != 0 goto onemore_uni
end_uni:
// Add the four sums together.
ADDPD X8, X7
MOVSD X7, X0
UNPCKHPD X7, X7
ADDSD X0, X7
MOVSD X7, sum+48(FP) // Return final sum.
RET
// func DdotInc(x, y []float64, n, incX, incY, ix, iy uintptr) (sum float64)
TEXT ·DotInc(SB), NOSPLIT, $0
MOVQ x+0(FP), R8
MOVQ y+24(FP), R9
MOVQ n+48(FP), CX
MOVQ incX+56(FP), R11
MOVQ incY+64(FP), R12
MOVQ ix+72(FP), R13
MOVQ iy+80(FP), R14
MOVSD $(0.0), X7 // sum = 0
LEAQ (R8)(R13*8), SI // p = &x[ix]
LEAQ (R9)(R14*8), DI // q = &y[ix]
SHLQ $3, R11 // incX *= sizeof(float64)
SHLQ $3, R12 // indY *= sizeof(float64)
SUBQ $2, CX // n -= 2
JL tail_inc // if n < 0 goto tail_inc
loop_inc:
// sum += *p * *q unrolled 2x.
MOVHPD (SI), X0
MOVHPD (DI), X1
ADDQ R11, SI // p += incX
ADDQ R12, DI // q += incY
MOVLPD (SI), X0
MOVLPD (DI), X1
ADDQ R11, SI // p += incX
ADDQ R12, DI // q += incY
MULPD X1, X0
ADDPD X0, X7
SUBQ $2, CX // n -= 2
JGE loop_inc // if n >= 0 goto loop_inc
tail_inc:
ADDQ $2, CX // n += 2
JLE end_inc // if n <= 0 goto end_inc
// sum += *p * *q for the last iteration if n is odd.
MOVSD (SI), X0
MULSD (DI), X0
ADDSD X0, X7
end_inc:
// Add the two sums together.
MOVSD X7, X0
UNPCKHPD X7, X7
ADDSD X0, X7
MOVSD X7, sum+88(FP) // Return final sum.
RET