Text file src/pkg/math/hypot_amd64.s

     1	// Copyright 2010 The Go 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	#include "textflag.h"
     6	
     7	#define PosInf 0x7FF0000000000000
     8	#define NaN 0x7FF8000000000001
     9	
    10	// func Hypot(p, q float64) float64
    11	TEXT ·Hypot(SB),NOSPLIT,$0
    12		// test bits for special cases
    13		MOVQ    p+0(FP), BX
    14		MOVQ    $~(1<<63), AX
    15		ANDQ    AX, BX // p = |p|
    16		MOVQ    q+8(FP), CX
    17		ANDQ    AX, CX // q = |q|
    18		MOVQ    $PosInf, AX
    19		CMPQ    AX, BX
    20		JLE     isInfOrNaN
    21		CMPQ    AX, CX
    22		JLE     isInfOrNaN
    23		// hypot = max * sqrt(1 + (min/max)**2)
    24		MOVQ    BX, X0
    25		MOVQ    CX, X1
    26		ORQ     CX, BX
    27		JEQ     isZero
    28		MOVAPD  X0, X2
    29		MAXSD   X1, X0
    30		MINSD   X2, X1
    31		DIVSD   X0, X1
    32		MULSD   X1, X1
    33		ADDSD   $1.0, X1
    34		SQRTSD  X1, X1
    35		MULSD   X1, X0
    36		MOVSD   X0, ret+16(FP)
    37		RET
    38	isInfOrNaN:
    39		CMPQ    AX, BX
    40		JEQ     isInf
    41		CMPQ    AX, CX
    42		JEQ     isInf
    43		MOVQ    $NaN, AX
    44		MOVQ    AX, ret+16(FP) // return NaN
    45		RET
    46	isInf:
    47		MOVQ    AX, ret+16(FP) // return +Inf
    48		RET
    49	isZero:
    50		MOVQ    $0, AX
    51		MOVQ    AX, ret+16(FP) // return 0
    52		RET

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