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,!appengine,!safe
6
7#include "textflag.h"
8
9// func DivTo(dst, x, y []float64)
10TEXT ·DivTo(SB), NOSPLIT, $0
11	MOVQ    dst_base+0(FP), DI // DI = &dst
12	MOVQ    dst_len+8(FP), CX  // CX = len(dst)
13	MOVQ    x_base+24(FP), SI  // SI = &x
14	MOVQ    y_base+48(FP), DX  // DX = &y
15	CMPQ    x_len+32(FP), CX   // CX = max( len(dst), len(x), len(y) )
16	CMOVQLE x_len+32(FP), CX
17	CMPQ    y_len+56(FP), CX
18	CMOVQLE y_len+56(FP), CX
19	MOVQ    CX, ret_len+80(FP) // len(ret) = CX
20	CMPQ    CX, $0             // if CX == 0 { return }
21	JE      div_end
22	XORQ    AX, AX             // i = 0
23	MOVQ    DX, BX
24	ANDQ    $15, BX            // BX = &y & OxF
25	JZ      div_no_trim        // if BX == 0 { goto div_no_trim }
26
27	// Align on 16-bit boundary
28	MOVSD (SI)(AX*8), X0 // X0 = s[i]
29	DIVSD (DX)(AX*8), X0 // X0 /= t[i]
30	MOVSD X0, (DI)(AX*8) // dst[i] = X0
31	INCQ  AX             // ++i
32	DECQ  CX             // --CX
33	JZ    div_end        // if CX == 0 { return }
34
35div_no_trim:
36	MOVQ CX, BX
37	ANDQ $7, BX         // BX = len(dst) % 8
38	SHRQ $3, CX         // CX = floor( len(dst) / 8 )
39	JZ   div_tail_start // if CX == 0 { goto div_tail_start }
40
41div_loop: // Loop unrolled 8x   do {
42	MOVUPS (SI)(AX*8), X0   // X0 = x[i:i+1]
43	MOVUPS 16(SI)(AX*8), X1
44	MOVUPS 32(SI)(AX*8), X2
45	MOVUPS 48(SI)(AX*8), X3
46	DIVPD  (DX)(AX*8), X0   // X0 /= y[i:i+1]
47	DIVPD  16(DX)(AX*8), X1
48	DIVPD  32(DX)(AX*8), X2
49	DIVPD  48(DX)(AX*8), X3
50	MOVUPS X0, (DI)(AX*8)   // dst[i:i+1] = X0
51	MOVUPS X1, 16(DI)(AX*8)
52	MOVUPS X2, 32(DI)(AX*8)
53	MOVUPS X3, 48(DI)(AX*8)
54	ADDQ   $8, AX           // i += 8
55	LOOP   div_loop         // } while --CX > 0
56	CMPQ   BX, $0           // if BX == 0 { return }
57	JE     div_end
58
59div_tail_start: // Reset loop registers
60	MOVQ BX, CX // Loop counter: CX = BX
61
62div_tail: // do {
63	MOVSD (SI)(AX*8), X0 // X0  = x[i]
64	DIVSD (DX)(AX*8), X0 // X0 /= y[i]
65	MOVSD X0, (DI)(AX*8)
66	INCQ  AX             // ++i
67	LOOP  div_tail       // } while --CX > 0
68
69div_end:
70	MOVQ DI, ret_base+72(FP) // &ret = &dst
71	MOVQ dst_cap+16(FP), DI  // cap(ret) = cap(dst)
72	MOVQ DI, ret_cap+88(FP)
73	RET
74