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| // 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 ·Hypot(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
|
|
