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// func Hypot(p, q float64) float64
8TEXT ·Hypot(SB),NOSPLIT,$0
9// test bits for not-finite
10	MOVL    p_hi+4(FP), AX   // high word p
11	ANDL    $0x7ff00000, AX
12	CMPL    AX, $0x7ff00000
13	JEQ     not_finite
14	MOVL    q_hi+12(FP), AX   // high word q
15	ANDL    $0x7ff00000, AX
16	CMPL    AX, $0x7ff00000
17	JEQ     not_finite
18	FMOVD   p+0(FP), F0  // F0=p
19	FABS                 // F0=|p|
20	FMOVD   q+8(FP), F0  // F0=q, F1=|p|
21	FABS                 // F0=|q|, F1=|p|
22	FUCOMI  F0, F1       // compare F0 to F1
23	JCC     2(PC)        // jump if F0 >= F1
24	FXCHD   F0, F1       // F0=|p| (larger), F1=|q| (smaller)
25	FTST                 // compare F0 to 0
26	FSTSW	AX
27	ANDW    $0x4000, AX
28	JNE     10(PC)       // jump if F0 = 0
29	FXCHD   F0, F1       // F0=q (smaller), F1=p (larger)
30	FDIVD   F1, F0       // F0=q(=q/p), F1=p
31	FMULD   F0, F0       // F0=q*q, F1=p
32	FLD1                 // F0=1, F1=q*q, F2=p
33	FADDDP  F0, F1       // F0=1+q*q, F1=p
34	FSQRT                // F0=sqrt(1+q*q), F1=p
35	FMULDP  F0, F1       // F0=p*sqrt(1+q*q)
36	FMOVDP  F0, ret+16(FP)
37	RET
38	FMOVDP  F0, F1       // F0=0
39	FMOVDP  F0, ret+16(FP)
40	RET
41not_finite:
42// test bits for -Inf or +Inf
43	MOVL    p_hi+4(FP), AX  // high word p
44	ORL     p_lo+0(FP), AX  // low word p
45	ANDL    $0x7fffffff, AX
46	CMPL    AX, $0x7ff00000
47	JEQ     is_inf
48	MOVL    q_hi+12(FP), AX  // high word q
49	ORL     q_lo+8(FP), AX   // low word q
50	ANDL    $0x7fffffff, AX
51	CMPL    AX, $0x7ff00000
52	JEQ     is_inf
53	MOVL    $0x7ff80000, ret_hi+20(FP)  // return NaN = 0x7FF8000000000001
54	MOVL    $0x00000001, ret_lo+16(FP)
55	RET
56is_inf:
57	MOVL    AX, ret_hi+20(FP)  // return +Inf = 0x7FF0000000000000
58	MOVL    $0x00000000, ret_lo+16(FP)
59	RET
60