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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,!gccgo,!safe
#include "textflag.h"
// func AxpyInc(alpha float32, x, y []float32, n, incX, incY, ix, iy uintptr)
TEXT ·AxpyInc(SB), NOSPLIT, $0
MOVQ n+56(FP), CX // CX = n
CMPQ CX, $0 // if n==0 { return }
JLE axpyi_end
MOVQ x_base+8(FP), SI // SI = &x
MOVQ y_base+32(FP), DI // DI = &y
MOVQ ix+80(FP), R8 // R8 = ix
MOVQ iy+88(FP), R9 // R9 = iy
LEAQ (SI)(R8*4), SI // SI = &(x[ix])
LEAQ (DI)(R9*4), DI // DI = &(y[iy])
MOVQ DI, DX // DX = DI Read Pointer for y
MOVQ incX+64(FP), R8 // R8 = incX
SHLQ $2, R8 // R8 *= sizeof(float32)
MOVQ incY+72(FP), R9 // R9 = incY
SHLQ $2, R9 // R9 *= sizeof(float32)
MOVSS alpha+0(FP), X0 // X0 = alpha
MOVSS X0, X1 // X1 = X0 // for pipelining
MOVQ CX, BX
ANDQ $3, BX // BX = n % 4
SHRQ $2, CX // CX = floor( n / 4 )
JZ axpyi_tail_start // if CX == 0 { goto axpyi_tail_start }
axpyi_loop: // Loop unrolled 4x do {
MOVSS (SI), X2 // X_i = x[i]
MOVSS (SI)(R8*1), X3
LEAQ (SI)(R8*2), SI // SI = &(SI[incX*2])
MOVSS (SI), X4
MOVSS (SI)(R8*1), X5
MULSS X1, X2 // X_i *= a
MULSS X0, X3
MULSS X1, X4
MULSS X0, X5
ADDSS (DX), X2 // X_i += y[i]
ADDSS (DX)(R9*1), X3
LEAQ (DX)(R9*2), DX // DX = &(DX[incY*2])
ADDSS (DX), X4
ADDSS (DX)(R9*1), X5
MOVSS X2, (DI) // y[i] = X_i
MOVSS X3, (DI)(R9*1)
LEAQ (DI)(R9*2), DI // DI = &(DI[incY*2])
MOVSS X4, (DI)
MOVSS X5, (DI)(R9*1)
LEAQ (SI)(R8*2), SI // SI = &(SI[incX*2]) // Increment addresses
LEAQ (DX)(R9*2), DX // DX = &(DX[incY*2])
LEAQ (DI)(R9*2), DI // DI = &(DI[incY*2])
LOOP axpyi_loop // } while --CX > 0
CMPQ BX, $0 // if BX == 0 { return }
JE axpyi_end
axpyi_tail_start: // Reset loop registers
MOVQ BX, CX // Loop counter: CX = BX
axpyi_tail: // do {
MOVSS (SI), X2 // X2 = x[i]
MULSS X1, X2 // X2 *= a
ADDSS (DI), X2 // X2 += y[i]
MOVSS X2, (DI) // y[i] = X2
ADDQ R8, SI // SI = &(SI[incX])
ADDQ R9, DI // DI = &(DI[incY])
LOOP axpyi_tail // } while --CX > 0
axpyi_end:
RET
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