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[/] [or1k/] [trunk/] [newlib-1.10.0/] [newlib/] [libm/] [math/] [ef_atan2.c] - Blame information for rev 1773

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/* ef_atan2.c -- float version of e_atan2.c.
 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
 */
 
/*
 * ====================================================
 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
 *
 * Developed at SunPro, a Sun Microsystems, Inc. business.
 * Permission to use, copy, modify, and distribute this
 * software is freely granted, provided that this notice
 * is preserved.
 * ====================================================
 *
 */
 
#include "fdlibm.h"
 
#ifdef __STDC__
static const float
#else
static float
#endif
tiny  = 1.0e-30,
zero  = 0.0,
pi_o_4  = 7.8539818525e-01, /* 0x3f490fdb */
pi_o_2  = 1.5707963705e+00, /* 0x3fc90fdb */
pi      = 3.1415925026e+00, /* 0x40490fda */
pi_lo   = 1.5099578832e-07; /* 0x34222168 */
 
#ifdef __STDC__
        float __ieee754_atan2f(float y, float x)
#else
        float __ieee754_atan2f(y,x)
        float  y,x;
#endif
{
        float z;
        __int32_t k,m,hx,hy,ix,iy;
 
        GET_FLOAT_WORD(hx,x);
        ix = hx&0x7fffffff;
        GET_FLOAT_WORD(hy,y);
        iy = hy&0x7fffffff;
        if(FLT_UWORD_IS_NAN(ix)||
           FLT_UWORD_IS_NAN(iy))        /* x or y is NaN */
           return x+y;
        if(hx==0x3f800000) return atanf(y);   /* x=1.0 */
        m = ((hy>>31)&1)|((hx>>30)&2);  /* 2*sign(x)+sign(y) */
 
    /* when y = 0 */
        if(FLT_UWORD_IS_ZERO(iy)) {
            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(FLT_UWORD_IS_ZERO(ix)) return (hy<0)?  -pi_o_2-tiny: pi_o_2+tiny;
 
    /* when x is INF */
        if(FLT_UWORD_IS_INFINITE(ix)) {
            if(FLT_UWORD_IS_INFINITE(iy)) {
                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  (float)3.0*pi_o_4+tiny;/*atan(+INF,-INF)*/
                    case 3: return (float)-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(FLT_UWORD_IS_INFINITE(iy)) return (hy<0)? -pi_o_2-tiny: pi_o_2+tiny;
 
    /* compute y/x */
        k = (iy-ix)>>23;
        if(k > 60) z=pi_o_2+(float)0.5*pi_lo;   /* |y/x| >  2**60 */
        else if(hx<0&&k<-60) z=0.0;      /* |y|/x < -2**60 */
        else z=atanf(fabsf(y/x));       /* safe to do y/x */
        switch (m) {
            case 0: return       z  ;    /* atan(+,+) */
            case 1: {
                      __uint32_t zh;
                      GET_FLOAT_WORD(zh,z);
                      SET_FLOAT_WORD(z,zh ^ 0x80000000);
                    }
                    return       z  ;   /* atan(-,+) */
            case 2: return  pi-(z-pi_lo);/* atan(+,-) */
            default: /* case 3 */
                    return  (z-pi_lo)-pi;/* atan(-,-) */
        }
}

Line No.	Rev	Author	Line
1	1010	ivang	`/* ef_atan2.c -- float version of e_atan2.c.`
2			`* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.`
3			`*/`
4
5			`/*`
6			`* ====================================================`
7			`* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.`
8			`*`
9			`* Developed at SunPro, a Sun Microsystems, Inc. business.`
10			`* Permission to use, copy, modify, and distribute this`
11			`* software is freely granted, provided that this notice`
12			`* is preserved.`
13			`* ====================================================`
14			`*`
15			`*/`
16
17			`#include "fdlibm.h"`
18
19			`#ifdef __STDC__`
20			`static const float`
21			`#else`
22			`static float`
23			`#endif`
24			`tiny = 1.0e-30,`
25			`zero = 0.0,`
26			`pi_o_4 = 7.8539818525e-01, /* 0x3f490fdb */`
27			`pi_o_2 = 1.5707963705e+00, /* 0x3fc90fdb */`
28			`pi = 3.1415925026e+00, /* 0x40490fda */`
29			`pi_lo = 1.5099578832e-07; /* 0x34222168 */`
30
31			`#ifdef __STDC__`
32			`float __ieee754_atan2f(float y, float x)`
33			`#else`
34			`float __ieee754_atan2f(y,x)`
35			`float y,x;`
36			`#endif`
37			`{`
38			`float z;`
39			`__int32_t k,m,hx,hy,ix,iy;`
40
41			`GET_FLOAT_WORD(hx,x);`
42			`ix = hx&0x7fffffff;`
43			`GET_FLOAT_WORD(hy,y);`
44			`iy = hy&0x7fffffff;`
45			`if(FLT_UWORD_IS_NAN(ix)\|\|`
46			`FLT_UWORD_IS_NAN(iy)) /* x or y is NaN */`
47			`return x+y;`
48			`if(hx==0x3f800000) return atanf(y); /* x=1.0 */`
49			`m = ((hy>>31)&1)\|((hx>>30)&2); /* 2sign(x)+sign(y) /`
50
51			`/* when y = 0 */`
52			`if(FLT_UWORD_IS_ZERO(iy)) {`
53			`switch(m) {`
54			`case 0:`
55			`case 1: return y; /* atan(+-0,+anything)=+-0 */`
56			`case 2: return pi+tiny;/* atan(+0,-anything) = pi */`
57			`case 3: return -pi-tiny;/* atan(-0,-anything) =-pi */`
58			`}`
59			`}`
60			`/* when x = 0 */`
61			`if(FLT_UWORD_IS_ZERO(ix)) return (hy<0)? -pi_o_2-tiny: pi_o_2+tiny;`
62
63			`/* when x is INF */`
64			`if(FLT_UWORD_IS_INFINITE(ix)) {`
65			`if(FLT_UWORD_IS_INFINITE(iy)) {`
66			`switch(m) {`
67			`case 0: return pi_o_4+tiny;/* atan(+INF,+INF) */`
68			`case 1: return -pi_o_4-tiny;/* atan(-INF,+INF) */`
69			`case 2: return (float)3.0pi_o_4+tiny;/atan(+INF,-INF)*/`
70			`case 3: return (float)-3.0pi_o_4-tiny;/atan(-INF,-INF)*/`
71			`}`
72			`} else {`
73			`switch(m) {`
74			`case 0: return zero ; /* atan(+...,+INF) */`
75			`case 1: return -zero ; /* atan(-...,+INF) */`
76			`case 2: return pi+tiny ; /* atan(+...,-INF) */`
77			`case 3: return -pi-tiny ; /* atan(-...,-INF) */`
78			`}`
79			`}`
80			`}`
81			`/* when y is INF */`
82			`if(FLT_UWORD_IS_INFINITE(iy)) return (hy<0)? -pi_o_2-tiny: pi_o_2+tiny;`
83
84			`/* compute y/x */`
85			`k = (iy-ix)>>23;`
86			`if(k > 60) z=pi_o_2+(float)0.5pi_lo; / \|y/x\| > 2*60 /`
87			`else if(hx<0&&k<-60) z=0.0; /* \|y\|/x < -2*60 /`
88			`else z=atanf(fabsf(y/x)); /* safe to do y/x */`
89			`switch (m) {`
90			`case 0: return z ; /* atan(+,+) */`
91			`case 1: {`
92			`__uint32_t zh;`
93			`GET_FLOAT_WORD(zh,z);`
94			`SET_FLOAT_WORD(z,zh ^ 0x80000000);`
95			`}`
96			`return z ; /* atan(-,+) */`
97			`case 2: return pi-(z-pi_lo);/* atan(+,-) */`
98			`default: /* case 3 */`
99			`return (z-pi_lo)-pi;/* atan(-,-) */`
100			`}`
101			`}`

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[/] [or1k/] [trunk/] [newlib-1.10.0/] [newlib/] [libm/] [math/] [ef_atan2.c] - Blame information for rev 1773