nlpodyssey/spago

// 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
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// 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