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.
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:
9 // Copyright (c) 2012 The Go Authors. All rights reserved.
11 // Redistribution and use in source and binary forms, with or without
12 // modification, are permitted provided that the following conditions are
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
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.
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.
37 //+build !noasm,!appengine
50 // func AxpyUnitaryTo(dst []float64, alpha float64, x, y []float64)
51 TEXT ·AxpyUnitaryTo(SB), NOSPLIT, $0
52 MOVQ dst_base+0(FP), DST_PTR // DST_PTR := &dst
53 MOVQ x_base+32(FP), X_PTR // X_PTR := &x
54 MOVQ y_base+56(FP), Y_PTR // Y_PTR := &y
55 MOVQ x_len+40(FP), LEN // LEN = min( len(x), len(y), len(dst) )
56 CMPQ y_len+64(FP), LEN
57 CMOVQLE y_len+64(FP), LEN
58 CMPQ dst_len+8(FP), LEN
59 CMOVQLE dst_len+8(FP), LEN
62 JE end // if LEN == 0 { return }
64 XORQ IDX, IDX // IDX = 0
65 MOVSD alpha+24(FP), ALPHA
66 SHUFPD $0, ALPHA, ALPHA // ALPHA := { alpha, alpha }
67 MOVQ Y_PTR, TAIL // Check memory alignment
68 ANDQ $15, TAIL // TAIL = &y % 16
69 JZ no_trim // if TAIL == 0 { goto no_trim }
71 // Align on 16-byte boundary
72 MOVSD (X_PTR), X2 // X2 := x[0]
73 MULSD ALPHA, X2 // X2 *= a
74 ADDSD (Y_PTR), X2 // X2 += y[0]
75 MOVSD X2, (DST_PTR) // y[0] = X2
78 JZ end // if LEN == 0 { return }
82 ANDQ $7, TAIL // TAIL := n % 8
83 SHRQ $3, LEN // LEN = floor( n / 8 )
84 JZ tail_start // if LEN == 0 { goto tail_start }
86 MOVUPS ALPHA, ALPHA_2 // ALPHA_2 := ALPHA for pipelining
89 // y[i] += alpha * x[i] unrolled 8x.
90 MOVUPS (X_PTR)(IDX*8), X2 // X_i = x[i]
91 MOVUPS 16(X_PTR)(IDX*8), X3
92 MOVUPS 32(X_PTR)(IDX*8), X4
93 MOVUPS 48(X_PTR)(IDX*8), X5
95 MULPD ALPHA, X2 // X_i *= alpha
100 ADDPD (Y_PTR)(IDX*8), X2 // X_i += y[i]
101 ADDPD 16(Y_PTR)(IDX*8), X3
102 ADDPD 32(Y_PTR)(IDX*8), X4
103 ADDPD 48(Y_PTR)(IDX*8), X5
105 MOVUPS X2, (DST_PTR)(IDX*8) // y[i] = X_i
106 MOVUPS X3, 16(DST_PTR)(IDX*8)
107 MOVUPS X4, 32(DST_PTR)(IDX*8)
108 MOVUPS X5, 48(DST_PTR)(IDX*8)
110 ADDQ $8, IDX // i += 8
112 JNZ loop // } while --LEN > 0
113 CMPQ TAIL, $0 // if TAIL == 0 { return }
116 tail_start: // Reset loop registers
117 MOVQ TAIL, LEN // Loop counter: LEN = TAIL
118 SHRQ $1, LEN // LEN = floor( TAIL / 2 )
119 JZ tail_one // if LEN == 0 { goto tail }
122 MOVUPS (X_PTR)(IDX*8), X2 // X2 = x[i]
123 MULPD ALPHA, X2 // X2 *= alpha
124 ADDPD (Y_PTR)(IDX*8), X2 // X2 += y[i]
125 MOVUPS X2, (DST_PTR)(IDX*8) // y[i] = X2
126 ADDQ $2, IDX // i += 2
128 JNZ tail_two // } while --LEN > 0
131 JZ end // if TAIL == 0 { goto end }
134 MOVSD (X_PTR)(IDX*8), X2 // X2 = x[i]
135 MULSD ALPHA, X2 // X2 *= a
136 ADDSD (Y_PTR)(IDX*8), X2 // X2 += y[i]
137 MOVSD X2, (DST_PTR)(IDX*8) // y[i] = X2