hypot_amd64.s

Documentation: math

		 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 archHypot(p, q float64) float64
		11TEXT ·archHypot(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
		38isInfOrNaN:
		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
		46isInf:
		47	MOVQ		AX, ret+16(FP) // return +Inf
		48	RET
		49isZero:
		50	MOVQ		$0, AX
		51	MOVQ		AX, ret+16(FP) // return 0
		52	RET
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