github.com/gopherd/gonum@v0.0.4/internal/asm/f64/divto_amd64.s (about)

     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 DivTo(dst, x, y []float64)
    10  TEXT ·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  
    35  div_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  
    41  div_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  
    59  div_tail_start: // Reset loop registers
    60  	MOVQ BX, CX // Loop counter: CX = BX
    61  
    62  div_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  
    69  div_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