| // 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 |