github.com/gopherd/gonum@v0.0.4/internal/asm/f64/dot_amd64.s (about)

     1  // Copyright ©2015 The Gonum 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  // Some of the loop unrolling code is copied from:
     6  // http://golang.org/src/math/big/arith_amd64.s
     7  // which is distributed under these terms:
     8  //
     9  // Copyright (c) 2012 The Go Authors. All rights reserved.
    10  //
    11  // Redistribution and use in source and binary forms, with or without
    12  // modification, are permitted provided that the following conditions are
    13  // met:
    14  //
    15  //    * Redistributions of source code must retain the above copyright
    16  // notice, this list of conditions and the following disclaimer.
    17  //    * Redistributions in binary form must reproduce the above
    18  // copyright notice, this list of conditions and the following disclaimer
    19  // in the documentation and/or other materials provided with the
    20  // distribution.
    21  //    * Neither the name of Google Inc. nor the names of its
    22  // contributors may be used to endorse or promote products derived from
    23  // this software without specific prior written permission.
    24  //
    25  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    26  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    27  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
    28  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    29  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    30  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
    31  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    32  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    33  // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    34  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    35  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
    36  
    37  // +build !noasm,!gccgo,!safe
    38  
    39  #include "textflag.h"
    40  
    41  // func DdotUnitary(x, y []float64) (sum float64)
    42  // This function assumes len(y) >= len(x).
    43  TEXT ·DotUnitary(SB), NOSPLIT, $0
    44  	MOVQ x+0(FP), R8
    45  	MOVQ x_len+8(FP), DI // n = len(x)
    46  	MOVQ y+24(FP), R9
    47  
    48  	MOVSD $(0.0), X7 // sum = 0
    49  	MOVSD $(0.0), X8 // sum = 0
    50  
    51  	MOVQ $0, SI   // i = 0
    52  	SUBQ $4, DI   // n -= 4
    53  	JL   tail_uni // if n < 0 goto tail_uni
    54  
    55  loop_uni:
    56  	// sum += x[i] * y[i] unrolled 4x.
    57  	MOVUPD 0(R8)(SI*8), X0
    58  	MOVUPD 0(R9)(SI*8), X1
    59  	MOVUPD 16(R8)(SI*8), X2
    60  	MOVUPD 16(R9)(SI*8), X3
    61  	MULPD  X1, X0
    62  	MULPD  X3, X2
    63  	ADDPD  X0, X7
    64  	ADDPD  X2, X8
    65  
    66  	ADDQ $4, SI   // i += 4
    67  	SUBQ $4, DI   // n -= 4
    68  	JGE  loop_uni // if n >= 0 goto loop_uni
    69  
    70  tail_uni:
    71  	ADDQ $4, DI  // n += 4
    72  	JLE  end_uni // if n <= 0 goto end_uni
    73  
    74  onemore_uni:
    75  	// sum += x[i] * y[i] for the remaining 1-3 elements.
    76  	MOVSD 0(R8)(SI*8), X0
    77  	MOVSD 0(R9)(SI*8), X1
    78  	MULSD X1, X0
    79  	ADDSD X0, X7
    80  
    81  	ADDQ $1, SI      // i++
    82  	SUBQ $1, DI      // n--
    83  	JNZ  onemore_uni // if n != 0 goto onemore_uni
    84  
    85  end_uni:
    86  	// Add the four sums together.
    87  	ADDPD    X8, X7
    88  	MOVSD    X7, X0
    89  	UNPCKHPD X7, X7
    90  	ADDSD    X0, X7
    91  	MOVSD    X7, sum+48(FP) // Return final sum.
    92  	RET
    93  
    94  // func DdotInc(x, y []float64, n, incX, incY, ix, iy uintptr) (sum float64)
    95  TEXT ·DotInc(SB), NOSPLIT, $0
    96  	MOVQ x+0(FP), R8
    97  	MOVQ y+24(FP), R9
    98  	MOVQ n+48(FP), CX
    99  	MOVQ incX+56(FP), R11
   100  	MOVQ incY+64(FP), R12
   101  	MOVQ ix+72(FP), R13
   102  	MOVQ iy+80(FP), R14
   103  
   104  	MOVSD $(0.0), X7      // sum = 0
   105  	LEAQ  (R8)(R13*8), SI // p = &x[ix]
   106  	LEAQ  (R9)(R14*8), DI // q = &y[ix]
   107  	SHLQ  $3, R11         // incX *= sizeof(float64)
   108  	SHLQ  $3, R12         // indY *= sizeof(float64)
   109  
   110  	SUBQ $2, CX   // n -= 2
   111  	JL   tail_inc // if n < 0 goto tail_inc
   112  
   113  loop_inc:
   114  	// sum += *p * *q unrolled 2x.
   115  	MOVHPD (SI), X0
   116  	MOVHPD (DI), X1
   117  	ADDQ   R11, SI  // p += incX
   118  	ADDQ   R12, DI  // q += incY
   119  	MOVLPD (SI), X0
   120  	MOVLPD (DI), X1
   121  	ADDQ   R11, SI  // p += incX
   122  	ADDQ   R12, DI  // q += incY
   123  
   124  	MULPD X1, X0
   125  	ADDPD X0, X7
   126  
   127  	SUBQ $2, CX   // n -= 2
   128  	JGE  loop_inc // if n >= 0 goto loop_inc
   129  
   130  tail_inc:
   131  	ADDQ $2, CX  // n += 2
   132  	JLE  end_inc // if n <= 0 goto end_inc
   133  
   134  	// sum += *p * *q for the last iteration if n is odd.
   135  	MOVSD (SI), X0
   136  	MULSD (DI), X0
   137  	ADDSD X0, X7
   138  
   139  end_inc:
   140  	// Add the two sums together.
   141  	MOVSD    X7, X0
   142  	UNPCKHPD X7, X7
   143  	ADDSD    X0, X7
   144  	MOVSD    X7, sum+88(FP) // Return final sum.
   145  	RET