1
/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
3
* ***** BEGIN LICENSE BLOCK *****
4
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
6
* The contents of this file are subject to the Mozilla Public License Version
7
* 1.1 (the "License"); you may not use this file except in compliance with
8
* the License. You may obtain a copy of the License at
9
* http://www.mozilla.org/MPL/
11
* Software distributed under the License is distributed on an "AS IS" basis,
12
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
13
* for the specific language governing rights and limitations under the
16
* The Original Code is Mozilla Communicator client code, released
19
* The Initial Developer of the Original Code is
20
* Sun Microsystems, Inc.
21
* Portions created by the Initial Developer are Copyright (C) 1998
22
* the Initial Developer. All Rights Reserved.
26
* Alternatively, the contents of this file may be used under the terms of
27
* either of the GNU General Public License Version 2 or later (the "GPL"),
28
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
29
* in which case the provisions of the GPL or the LGPL are applicable instead
30
* of those above. If you wish to allow use of your version of this file only
31
* under the terms of either the GPL or the LGPL, and not to allow others to
32
* use your version of this file under the terms of the MPL, indicate your
33
* decision by deleting the provisions above and replace them with the notice
34
* and other provisions required by the GPL or the LGPL. If you do not delete
35
* the provisions above, a recipient may use your version of this file under
36
* the terms of any one of the MPL, the GPL or the LGPL.
38
* ***** END LICENSE BLOCK ***** */
40
/* @(#)e_atan2.c 1.3 95/01/18 */
42
* ====================================================
43
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
45
* Developed at SunSoft, a Sun Microsystems, Inc. business.
46
* Permission to use, copy, modify, and distribute this
47
* software is freely granted, provided that this notice
49
* ====================================================
53
/* __ieee754_atan2(y,x)
55
* 1. Reduce y to positive by atan2(y,x)=-atan2(-y,x).
56
* 2. Reduce x to positive by (if x and y are unexceptional):
57
* ARG (x+iy) = arctan(y/x) ... if x > 0,
58
* ARG (x+iy) = pi - arctan[y/(-x)] ... if x < 0,
62
* ATAN2((anything), NaN ) is NaN;
63
* ATAN2(NAN , (anything) ) is NaN;
64
* ATAN2(+-0, +(anything but NaN)) is +-0 ;
65
* ATAN2(+-0, -(anything but NaN)) is +-pi ;
66
* ATAN2(+-(anything but 0 and NaN), 0) is +-pi/2;
67
* ATAN2(+-(anything but INF and NaN), +INF) is +-0 ;
68
* ATAN2(+-(anything but INF and NaN), -INF) is +-pi;
69
* ATAN2(+-INF,+INF ) is +-pi/4 ;
70
* ATAN2(+-INF,-INF ) is +-3pi/4;
71
* ATAN2(+-INF, (anything but,0,NaN, and INF)) is +-pi/2;
74
* The hexadecimal values are the intended ones for the following
75
* constants. The decimal values may be used, provided that the
76
* compiler will convert from decimal to binary accurately enough
77
* to produce the hexadecimal values shown.
89
pi_o_4 = 7.8539816339744827900E-01, /* 0x3FE921FB, 0x54442D18 */
90
pi_o_2 = 1.5707963267948965580E+00, /* 0x3FF921FB, 0x54442D18 */
91
pi = 3.1415926535897931160E+00, /* 0x400921FB, 0x54442D18 */
92
pi_lo = 1.2246467991473531772E-16; /* 0x3CA1A626, 0x33145C07 */
95
double __ieee754_atan2(double y, double x)
97
double __ieee754_atan2(y,x)
101
fd_twoints ux, uy, uz;
107
hx = __HI(ux); ix = hx&0x7fffffff;
109
hy = __HI(uy); iy = hy&0x7fffffff;
111
if(((ix|((lx|-(int)lx)>>31))>0x7ff00000)||
112
((iy|((ly|-(int)ly)>>31))>0x7ff00000)) /* x or y is NaN */
114
if(((hx-0x3ff00000)|lx)==0) return fd_atan(y); /* x=1.0 */
115
m = ((hy>>31)&1)|((hx>>30)&2); /* 2*sign(x)+sign(y) */
121
case 1: return y; /* atan(+-0,+anything)=+-0 */
122
case 2: return pi+tiny;/* atan(+0,-anything) = pi */
123
case 3: return -pi-tiny;/* atan(-0,-anything) =-pi */
127
if((ix|lx)==0) return (hy<0)? -pi_o_2-tiny: pi_o_2+tiny;
133
case 0: return pi_o_4+tiny;/* atan(+INF,+INF) */
134
case 1: return -pi_o_4-tiny;/* atan(-INF,+INF) */
135
case 2: return 3.0*pi_o_4+tiny;/*atan(+INF,-INF)*/
136
case 3: return -3.0*pi_o_4-tiny;/*atan(-INF,-INF)*/
140
case 0: return zero ; /* atan(+...,+INF) */
141
case 1: return -zero ; /* atan(-...,+INF) */
142
case 2: return pi+tiny ; /* atan(+...,-INF) */
143
case 3: return -pi-tiny ; /* atan(-...,-INF) */
148
if(iy==0x7ff00000) return (hy<0)? -pi_o_2-tiny: pi_o_2+tiny;
152
if(k > 60) z=pi_o_2+0.5*pi_lo; /* |y/x| > 2**60 */
153
else if(hx<0&&k<-60) z=0.0; /* |y|/x < -2**60 */
154
else z=fd_atan(fd_fabs(y/x)); /* safe to do y/x */
156
case 0: return z ; /* atan(+,+) */
158
__HI(uz) ^= 0x80000000;
160
return z ; /* atan(-,+) */
161
case 2: return pi-(z-pi_lo);/* atan(+,-) */
162
default: /* case 3 */
163
return (z-pi_lo)-pi;/* atan(-,-) */
added
removed
src/dom/js/fdlibm/e_atan2.c
