1 // Copyright ©2016 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 // +build !noasm,!appengine
9 TEXT ·CumProd(SB), NOSPLIT, $0
10 MOVQ dst_base+0(FP), DI // DI = &dst
11 MOVQ dst_len+8(FP), CX // CX = len(dst)
12 MOVQ s_base+24(FP), SI // SI = &s
13 CMPQ s_len+32(FP), CX // CX = max( CX, len(s) )
14 CMOVQLE s_len+32(FP), CX
15 MOVQ CX, ret_len+56(FP) // len(ret) = CX
16 CMPQ CX, $0 // if CX == 0 { return }
20 MOVSD (SI), X5 // p_prod = { s[0], s[0] }
22 MOVSD X5, (DI) // dst[0] = s[0]
25 JZ cp_end // if CX == 0 { return }
28 ANDQ $3, BX // BX = CX % 4
29 SHRQ $2, CX // CX = floor( CX / 4 )
30 JZ cp_tail_start // if CX == 0 { goto cp_tail_start }
32 cp_loop: // Loop unrolled 4x do {
33 MOVUPS (SI)(AX*8), X0 // X0 = s[i:i+1]
34 MOVUPS 16(SI)(AX*8), X2
35 MOVAPS X0, X1 // X1 = X0
37 SHUFPD $1, X1, X1 // { X1[0], X1[1] } = { X1[1], X1[0] }
39 MULPD X0, X1 // X1 *= X0
41 SHUFPD $2, X1, X0 // { X0[0], X0[1] } = { X0[0], X1[1] }
42 SHUFPD $3, X1, X1 // { X1[0], X1[1] } = { X1[1], X1[1] }
45 MULPD X5, X0 // X0 *= p_prod
46 MULPD X1, X5 // p_prod *= X1
48 MOVUPS X0, (DI)(AX*8) // dst[i] = X0
49 MOVUPS X2, 16(DI)(AX*8)
52 LOOP cp_loop // } while --CX > 0
54 // if BX == 0 { return }
58 cp_tail_start: // Reset loop registers
59 MOVQ BX, CX // Loop counter: CX = BX
62 MULSD (SI)(AX*8), X5 // p_prod *= s[i]
63 MOVSD X5, (DI)(AX*8) // dst[i] = p_prod
65 LOOP cp_tail // } while --CX > 0
68 MOVQ DI, ret_base+48(FP) // &ret = &dst
69 MOVQ dst_cap+16(FP), SI // cap(ret) = cap(dst)
70 MOVQ SI, ret_cap+64(FP)