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// 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,!appengine
#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