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 // func Add(dst, s []float64)
10 TEXT ·Add(SB), NOSPLIT, $0
11 MOVQ dst_base+0(FP), DI // DI = &dst
12 MOVQ dst_len+8(FP), CX // CX = len(dst)
13 MOVQ s_base+24(FP), SI // SI = &s
14 CMPQ s_len+32(FP), CX // CX = max( CX, len(s) )
15 CMOVQLE s_len+32(FP), CX
16 CMPQ CX, $0 // if CX == 0 { return }
20 ANDQ $0x0F, BX // BX = &dst & 15
21 JZ add_no_trim // if BX == 0 { goto add_no_trim }
23 // Align on 16-bit boundary
24 MOVSD (SI)(AX*8), X0 // X0 = s[i]
25 ADDSD (DI)(AX*8), X0 // X0 += dst[i]
26 MOVSD X0, (DI)(AX*8) // dst[i] = X0
29 JE add_end // if CX == 0 { return }
33 ANDQ $7, BX // BX = len(dst) % 8
34 SHRQ $3, CX // CX = floor( len(dst) / 8 )
35 JZ add_tail_start // if CX == 0 { goto add_tail_start }
37 add_loop: // Loop unrolled 8x do {
38 MOVUPS (SI)(AX*8), X0 // X_i = s[i:i+1]
39 MOVUPS 16(SI)(AX*8), X1
40 MOVUPS 32(SI)(AX*8), X2
41 MOVUPS 48(SI)(AX*8), X3
42 ADDPD (DI)(AX*8), X0 // X_i += dst[i:i+1]
43 ADDPD 16(DI)(AX*8), X1
44 ADDPD 32(DI)(AX*8), X2
45 ADDPD 48(DI)(AX*8), X3
46 MOVUPS X0, (DI)(AX*8) // dst[i:i+1] = X_i
47 MOVUPS X1, 16(DI)(AX*8)
48 MOVUPS X2, 32(DI)(AX*8)
49 MOVUPS X3, 48(DI)(AX*8)
51 LOOP add_loop // } while --CX > 0
52 CMPQ BX, $0 // if BX == 0 { return }
55 add_tail_start: // Reset loop registers
56 MOVQ BX, CX // Loop counter: CX = BX
59 MOVSD (SI)(AX*8), X0 // X0 = s[i]
60 ADDSD (DI)(AX*8), X0 // X0 += dst[i]
61 MOVSD X0, (DI)(AX*8) // dst[i] = X0
63 LOOP add_tail // } while --CX > 0