blob: d7983a7d7b075eb6278bf261c221fcfe9325fc8a [file] [log] [blame]
// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#include "textflag.h"
#define PosInf 0x7FF0000000000000
#define NaN 0x7FF8000000000001
// func Hypot(p, q float64) float64
TEXT ┬ĚHypot(SB),NOSPLIT,$0
// test bits for special cases
MOVQ p+0(FP), BX
MOVQ $~(1<<63), AX
ANDQ AX, BX // p = |p|
MOVQ q+8(FP), CX
ANDQ AX, CX // q = |q|
MOVQ $PosInf, AX
CMPQ AX, BX
JLE isInfOrNaN
CMPQ AX, CX
JLE isInfOrNaN
// hypot = max * sqrt(1 + (min/max)**2)
MOVQ BX, X0
MOVQ CX, X1
ORQ CX, BX
JEQ isZero
MOVAPD X0, X2
MAXSD X1, X0
MINSD X2, X1
DIVSD X0, X1
MULSD X1, X1
ADDSD $1.0, X1
SQRTSD X1, X1
MULSD X1, X0
MOVSD X0, ret+16(FP)
RET
isInfOrNaN:
CMPQ AX, BX
JEQ isInf
CMPQ AX, CX
JEQ isInf
MOVQ $NaN, AX
MOVQ AX, ret+16(FP) // return NaN
RET
isInf:
MOVQ AX, ret+16(FP) // return +Inf
RET
isZero:
MOVQ $0, AX
MOVQ AX, ret+16(FP) // return 0
RET