| // Copyright ©2016 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" |
| |
| #define MOVDDUP_ALPHA LONG $0x44120FF2; WORD $0x0824 // @ MOVDDUP XMM0, 8[RSP] |
| |
| #define X_PTR SI |
| #define DST_PTR DI |
| #define IDX AX |
| #define LEN CX |
| #define TAIL BX |
| #define ALPHA X0 |
| #define ALPHA_2 X1 |
| |
| // func ScalUnitary(alpha float64, x []float64) |
| TEXT ·ScalUnitary(SB), NOSPLIT, $0 |
| MOVDDUP_ALPHA // ALPHA = { alpha, alpha } |
| MOVQ x_base+8(FP), X_PTR // X_PTR = &x |
| MOVQ x_len+16(FP), LEN // LEN = len(x) |
| CMPQ LEN, $0 |
| JE end // if LEN == 0 { return } |
| XORQ IDX, IDX // IDX = 0 |
| |
| MOVQ LEN, TAIL |
| ANDQ $7, TAIL // TAIL = LEN % 8 |
| SHRQ $3, LEN // LEN = floor( LEN / 8 ) |
| JZ tail_start // if LEN == 0 { goto tail_start } |
| |
| MOVUPS ALPHA, ALPHA_2 |
| |
| loop: // do { // x[i] *= alpha unrolled 8x. |
| MOVUPS (X_PTR)(IDX*8), X2 // X_i = x[i] |
| MOVUPS 16(X_PTR)(IDX*8), X3 |
| MOVUPS 32(X_PTR)(IDX*8), X4 |
| MOVUPS 48(X_PTR)(IDX*8), X5 |
| |
| MULPD ALPHA, X2 // X_i *= ALPHA |
| MULPD ALPHA_2, X3 |
| MULPD ALPHA, X4 |
| MULPD ALPHA_2, X5 |
| |
| MOVUPS X2, (X_PTR)(IDX*8) // x[i] = X_i |
| MOVUPS X3, 16(X_PTR)(IDX*8) |
| MOVUPS X4, 32(X_PTR)(IDX*8) |
| MOVUPS X5, 48(X_PTR)(IDX*8) |
| |
| ADDQ $8, IDX // i += 8 |
| DECQ LEN |
| JNZ loop // while --LEN > 0 |
| CMPQ TAIL, $0 |
| JE end // if TAIL == 0 { return } |
| |
| tail_start: // Reset loop registers |
| MOVQ TAIL, LEN // Loop counter: LEN = TAIL |
| SHRQ $1, LEN // LEN = floor( TAIL / 2 ) |
| JZ tail_one // if n == 0 goto end |
| |
| tail_two: // do { |
| MOVUPS (X_PTR)(IDX*8), X2 // X_i = x[i] |
| MULPD ALPHA, X2 // X_i *= ALPHA |
| MOVUPS X2, (X_PTR)(IDX*8) // x[i] = X_i |
| ADDQ $2, IDX // i += 2 |
| DECQ LEN |
| JNZ tail_two // while --LEN > 0 |
| |
| ANDQ $1, TAIL |
| JZ end // if TAIL == 0 { return } |
| |
| tail_one: |
| // x[i] *= alpha for the remaining element. |
| MOVSD (X_PTR)(IDX*8), X2 |
| MULSD ALPHA, X2 |
| MOVSD X2, (X_PTR)(IDX*8) |
| |
| end: |
| RET |
