DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

#### Mercurial (d38398e5144e)

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124
``````
``````/* @(#)e_atan2.c 1.3 95/01/18 */
``````/*
`````` * ====================================================
`````` * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
`````` *
`````` * Developed at SunSoft, a Sun Microsystems, Inc. business.
`````` * Permission to use, copy, modify, and distribute this
`````` * software is freely granted, provided that this notice
`````` * is preserved.
`````` * ====================================================
`````` *
`````` */
``````
``````//#include <sys/cdefs.h>
``````//__FBSDID("\$FreeBSD\$");
``````
``````/* __ieee754_atan2(y,x)
`````` * Method :
`````` *	1. Reduce y to positive by atan2(y,x)=-atan2(-y,x).
`````` *	2. Reduce x to positive by (if x and y are unexceptional):
`````` *		ARG (x+iy) = arctan(y/x)   	   ... if x > 0,
`````` *		ARG (x+iy) = pi - arctan[y/(-x)]   ... if x < 0,
`````` *
`````` * Special cases:
`````` *
`````` *	ATAN2((anything), NaN ) is NaN;
`````` *	ATAN2(NAN , (anything) ) is NaN;
`````` *	ATAN2(+-0, +(anything but NaN)) is +-0  ;
`````` *	ATAN2(+-0, -(anything but NaN)) is +-pi ;
`````` *	ATAN2(+-(anything but 0 and NaN), 0) is +-pi/2;
`````` *	ATAN2(+-(anything but INF and NaN), +INF) is +-0 ;
`````` *	ATAN2(+-(anything but INF and NaN), -INF) is +-pi;
`````` *	ATAN2(+-INF,+INF ) is +-pi/4 ;
`````` *	ATAN2(+-INF,-INF ) is +-3pi/4;
`````` *	ATAN2(+-INF, (anything but,0,NaN, and INF)) is +-pi/2;
`````` *
`````` * Constants:
`````` * The hexadecimal values are the intended ones for the following
`````` * constants. The decimal values may be used, provided that the
`````` * compiler will convert from decimal to binary accurately enough
`````` * to produce the hexadecimal values shown.
`````` */
``````
``````#include <float.h>
``````
``````#include "math_private.h"
``````
``````static volatile double
``````tiny  = 1.0e-300;
``````static const double
``````zero  = 0.0,
``````pi_o_4  = 7.8539816339744827900E-01, /* 0x3FE921FB, 0x54442D18 */
``````pi_o_2  = 1.5707963267948965580E+00, /* 0x3FF921FB, 0x54442D18 */
``````pi      = 3.1415926535897931160E+00; /* 0x400921FB, 0x54442D18 */
``````static volatile double
``````pi_lo   = 1.2246467991473531772E-16; /* 0x3CA1A626, 0x33145C07 */
``````
``````double
``````__ieee754_atan2(double y, double x)
``````{
``````	double z;
``````	int32_t k,m,hx,hy,ix,iy;
``````	u_int32_t lx,ly;
``````
``````	EXTRACT_WORDS(hx,lx,x);
``````	ix = hx&0x7fffffff;
``````	EXTRACT_WORDS(hy,ly,y);
``````	iy = hy&0x7fffffff;
``````	if(((ix|((lx|-lx)>>31))>0x7ff00000)||
``````	   ((iy|((ly|-ly)>>31))>0x7ff00000))	/* x or y is NaN */
``````	   return x+y;
``````	if((hx-0x3ff00000|lx)==0) return atan(y);   /* x=1.0 */
``````	m = ((hy>>31)&1)|((hx>>30)&2);	/* 2*sign(x)+sign(y) */
``````
``````    /* when y = 0 */
``````	if((iy|ly)==0) {
``````	    switch(m) {
``````		case 0:
``````		case 1: return y; 	/* atan(+-0,+anything)=+-0 */
``````		case 2: return  pi+tiny;/* atan(+0,-anything) = pi */
``````		case 3: return -pi-tiny;/* atan(-0,-anything) =-pi */
``````	    }
``````	}
``````    /* when x = 0 */
``````	if((ix|lx)==0) return (hy<0)?  -pi_o_2-tiny: pi_o_2+tiny;
``````
``````    /* when x is INF */
``````	if(ix==0x7ff00000) {
``````	    if(iy==0x7ff00000) {
``````		switch(m) {
``````		    case 0: return  pi_o_4+tiny;/* atan(+INF,+INF) */
``````		    case 1: return -pi_o_4-tiny;/* atan(-INF,+INF) */
``````		    case 2: return  3.0*pi_o_4+tiny;/*atan(+INF,-INF)*/
``````		    case 3: return -3.0*pi_o_4-tiny;/*atan(-INF,-INF)*/
``````		}
``````	    } else {
``````		switch(m) {
``````		    case 0: return  zero  ;	/* atan(+...,+INF) */
``````		    case 1: return -zero  ;	/* atan(-...,+INF) */
``````		    case 2: return  pi+tiny  ;	/* atan(+...,-INF) */
``````		    case 3: return -pi-tiny  ;	/* atan(-...,-INF) */
``````		}
``````	    }
``````	}
``````    /* when y is INF */
``````	if(iy==0x7ff00000) return (hy<0)? -pi_o_2-tiny: pi_o_2+tiny;
``````
``````    /* compute y/x */
``````	k = (iy-ix)>>20;
``````	if(k > 60) {		 	/* |y/x| >  2**60 */
``````	    z=pi_o_2+0.5*pi_lo;
``````	    m&=1;
``````	}
``````	else if(hx<0&&k<-60) z=0.0; 	/* 0 > |y|/x > -2**-60 */
``````	else z=atan(fabs(y/x));		/* safe to do y/x */
``````	switch (m) {
``````	    case 0: return       z  ;	/* atan(+,+) */
``````	    case 1: return      -z  ;	/* atan(-,+) */
``````	    case 2: return  pi-(z-pi_lo);/* atan(+,-) */
``````	    default: /* case 3 */
``````	    	    return  (z-pi_lo)-pi;/* atan(-,-) */
``````	}
``````}
``````