| // 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. |
| |
| // +build !noasm,!gccgo,!safe |
| |
| #include "textflag.h" |
| |
| // func Addconst(alpha float64, x []float64) |
| TEXT ·AddConst(SB), NOSPLIT, $0 |
| MOVQ x_base+8(FP), SI // SI = &x |
| MOVQ x_len+16(FP), CX // CX = len(x) |
| CMPQ CX, $0 // if len(x) == 0 { return } |
| JE ac_end |
| MOVSD alpha+0(FP), X4 // X4 = { a, a } |
| SHUFPD $0, X4, X4 |
| MOVUPS X4, X5 // X5 = X4 |
| XORQ AX, AX // i = 0 |
| MOVQ CX, BX |
| ANDQ $7, BX // BX = len(x) % 8 |
| SHRQ $3, CX // CX = floor( len(x) / 8 ) |
| JZ ac_tail_start // if CX == 0 { goto ac_tail_start } |
| |
| ac_loop: // Loop unrolled 8x do { |
| MOVUPS (SI)(AX*8), X0 // X_i = s[i:i+1] |
| MOVUPS 16(SI)(AX*8), X1 |
| MOVUPS 32(SI)(AX*8), X2 |
| MOVUPS 48(SI)(AX*8), X3 |
| ADDPD X4, X0 // X_i += a |
| ADDPD X5, X1 |
| ADDPD X4, X2 |
| ADDPD X5, X3 |
| MOVUPS X0, (SI)(AX*8) // s[i:i+1] = X_i |
| MOVUPS X1, 16(SI)(AX*8) |
| MOVUPS X2, 32(SI)(AX*8) |
| MOVUPS X3, 48(SI)(AX*8) |
| ADDQ $8, AX // i += 8 |
| LOOP ac_loop // } while --CX > 0 |
| CMPQ BX, $0 // if BX == 0 { return } |
| JE ac_end |
| |
| ac_tail_start: // Reset loop counters |
| MOVQ BX, CX // Loop counter: CX = BX |
| |
| ac_tail: // do { |
| MOVSD (SI)(AX*8), X0 // X0 = s[i] |
| ADDSD X4, X0 // X0 += a |
| MOVSD X0, (SI)(AX*8) // s[i] = X0 |
| INCQ AX // ++i |
| LOOP ac_tail // } while --CX > 0 |
| |
| ac_end: |
| RET |
