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.
4
5// +build !noasm,!gccgo,!safe
6
7#include "textflag.h"
8
9// func Add(dst, s []float64)
10TEXT ·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 }
17	JE      add_end
18	XORQ    AX, AX
19	MOVQ    DI, BX
20	ANDQ    $0x0F, BX          // BX = &dst & 15
21	JZ      add_no_trim        // if BX == 0 { goto add_no_trim }
22
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
27	INCQ  AX             // i++
28	DECQ  CX             // --CX
29	JE    add_end        // if CX == 0 { return  }
30
31add_no_trim:
32	MOVQ CX, BX
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 }
36
37add_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)
50	ADDQ   $8, AX           // i += 8
51	LOOP   add_loop         // } while --CX > 0
52	CMPQ   BX, $0           // if BX == 0 { return }
53	JE     add_end
54
55add_tail_start: // Reset loop registers
56	MOVQ BX, CX // Loop counter: CX = BX
57
58add_tail: // do {
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
62	INCQ  AX             // ++i
63	LOOP  add_tail       // } while --CX > 0
64
65add_end:
66	RET
67