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/* @(#)w_pow.c 5.2 93/10/01 */
/*
 * ====================================================
 * 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.
 * ====================================================
 */
 
/*
FUNCTION
        <<pow>>, <<powf>>---x to the power y
INDEX
        pow
INDEX
        powf
 
 
ANSI_SYNOPSIS
        #include <math.h>
        double pow(double <[x]>, double <[y]>);
        float powf(float <[x]>, float <[y]>);
 
TRAD_SYNOPSIS
        #include <math.h>
        double pow(<[x]>, <[y]>);
        double <[x]>, <[y]>;
 
        float powf(<[x]>, <[y]>);
        float <[x]>, <[y]>;
 
DESCRIPTION
        <<pow>> and <<powf>> calculate <[x]> raised to the exponent <[y]>.
        @tex
        (That is, $x^y$.)
        @end tex
 
RETURNS
        On success, <<pow>> and <<powf>> return the value calculated.
 
        When the argument values would produce overflow, <<pow>>
        returns <<HUGE_VAL>> and set <<errno>> to <<ERANGE>>.  If the
        argument <[x]> passed to <<pow>> or <<powf>> is a negative
        noninteger, and <[y]> is also not an integer, then <<errno>>
        is set to <<EDOM>>.  If <[x]> and <[y]> are both 0, then
        <<pow>> and <<powf>> return <<1>>.
 
        You can modify error handling for these functions using <<matherr>>.
 
PORTABILITY
        <<pow>> is ANSI C. <<powf>> is an extension.  */
 
/*
 * wrapper pow(x,y) return x**y
 */
 
#include "fdlibm.h"
#include <errno.h>
 
#ifndef _DOUBLE_IS_32BITS
 
#ifdef __STDC__
        double pow(double x, double y)  /* wrapper pow */
#else
        double pow(x,y)                 /* wrapper pow */
        double x,y;
#endif
{
#ifdef _IEEE_LIBM
        return  __ieee754_pow(x,y);
#else
        double z;
#ifndef HUGE_VAL 
#define HUGE_VAL inf
        double inf = 0.0;
 
        SET_HIGH_WORD(inf,0x7ff00000);  /* set inf to infinite */
#endif
        struct exception exc;
        z=__ieee754_pow(x,y);
        if(_LIB_VERSION == _IEEE_|| isnan(y)) return z;
        if(isnan(x)) {
            if(y==0.0) {
                /* pow(NaN,0.0) */
                /* error only if _LIB_VERSION == _SVID_ & _XOPEN_ */
                exc.type = DOMAIN;
                exc.name = "pow";
                exc.err = 0;
                exc.arg1 = x;
                exc.arg2 = y;
                exc.retval = 1.0;
                if (_LIB_VERSION == _IEEE_ ||
                    _LIB_VERSION == _POSIX_) exc.retval = 1.0;
                else if (!matherr(&exc)) {
                        errno = EDOM;
                }
                if (exc.err != 0)
                   errno = exc.err;
                return exc.retval;
            } else
                return z;
        }
        if(x==0.0){
            if(y==0.0) {
                /* pow(0.0,0.0) */
                /* error only if _LIB_VERSION == _SVID_ */
                exc.type = DOMAIN;
                exc.name = "pow";
                exc.err = 0;
                exc.arg1 = x;
                exc.arg2 = y;
                exc.retval = 0.0;
                if (_LIB_VERSION != _SVID_) exc.retval = 1.0;
                else if (!matherr(&exc)) {
                        errno = EDOM;
                }
                if (exc.err != 0)
                   errno = exc.err;
                return exc.retval;
            }
            if(finite(y)&&y<0.0) {
                /* 0**neg */
                exc.type = DOMAIN;
                exc.name = "pow";
                exc.err = 0;
                exc.arg1 = x;
                exc.arg2 = y;
                if (_LIB_VERSION == _SVID_)
                  exc.retval = 0.0;
                else
                  exc.retval = -HUGE_VAL;
                if (_LIB_VERSION == _POSIX_)
                  errno = EDOM;
                else if (!matherr(&exc)) {
                  errno = EDOM;
                }
                if (exc.err != 0)
                   errno = exc.err;
                return exc.retval;
            }
            return z;
        }
        if(!finite(z)) {
            if(finite(x)&&finite(y)) {
                if(isnan(z)) {
                    /* neg**non-integral */
                    exc.type = DOMAIN;
                    exc.name = "pow";
                    exc.err = 0;
                    exc.arg1 = x;
                    exc.arg2 = y;
                    if (_LIB_VERSION == _SVID_)
                        exc.retval = 0.0;
                    else
                        exc.retval = 0.0/0.0;   /* X/Open allow NaN */
                    if (_LIB_VERSION == _POSIX_)
                        errno = EDOM;
                    else if (!matherr(&exc)) {
                        errno = EDOM;
                    }
                    if (exc.err != 0)
                        errno = exc.err;
                    return exc.retval;
                } else {
                    /* pow(x,y) overflow */
                    exc.type = OVERFLOW;
                    exc.name = "pow";
                    exc.err = 0;
                    exc.arg1 = x;
                    exc.arg2 = y;
                    if (_LIB_VERSION == _SVID_) {
                       exc.retval = HUGE;
                       y *= 0.5;
                       if(x<0.0&&rint(y)!=y) exc.retval = -HUGE;
                    } else {
                       exc.retval = HUGE_VAL;
                       y *= 0.5;
                       if(x<0.0&&rint(y)!=y) exc.retval = -HUGE_VAL;
                    }
                    if (_LIB_VERSION == _POSIX_)
                        errno = ERANGE;
                    else if (!matherr(&exc)) {
                        errno = ERANGE;
                    }
                    if (exc.err != 0)
                        errno = exc.err;
                    return exc.retval;
                }
            }
        }
        if(z==0.0&&finite(x)&&finite(y)) {
            /* pow(x,y) underflow */
            exc.type = UNDERFLOW;
            exc.name = "pow";
            exc.err = 0;
            exc.arg1 = x;
            exc.arg2 = y;
            exc.retval =  0.0;
            if (_LIB_VERSION == _POSIX_)
                errno = ERANGE;
            else if (!matherr(&exc)) {
                errno = ERANGE;
            }
            if (exc.err != 0)
                errno = exc.err;
            return exc.retval;
        }
        return z;
#endif
}
 
#endif /* defined(_DOUBLE_IS_32BITS) */
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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[/] [openrisc/] [trunk/] [gnu-old/] [newlib-1.17.0/] [newlib/] [libm/] [math/] [w_pow.c] - Blame information for rev 855

Line No.	Rev	Author	Line
1	148	jeremybenn
2
3			`/* @(#)w_pow.c 5.2 93/10/01 */`
4			`/*`
5			`* ====================================================`
6			`* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.`
7			`*`
8			`* Developed at SunPro, a Sun Microsystems, Inc. business.`
9			`* Permission to use, copy, modify, and distribute this`
10			`* software is freely granted, provided that this notice`
11			`* is preserved.`
12			`* ====================================================`
13			`*/`
14
15			`/*`
16			`FUNCTION`
17			`<<pow>>, <<powf>>---x to the power y`
18			`INDEX`
19			`pow`
20			`INDEX`
21			`powf`
22
23
24			`ANSI_SYNOPSIS`
25			`#include <math.h>`
26			`double pow(double <[x]>, double <[y]>);`
27			`float powf(float <[x]>, float <[y]>);`
28
29			`TRAD_SYNOPSIS`
30			`#include <math.h>`
31			`double pow(<[x]>, <[y]>);`
32			`double <[x]>, <[y]>;`
33
34			`float powf(<[x]>, <[y]>);`
35			`float <[x]>, <[y]>;`
36
37			`DESCRIPTION`
38			`<<pow>> and <<powf>> calculate <[x]> raised to the exponent <[y]>.`
39			`@tex`
40			`(That is, $x^y$.)`
41			`@end tex`
42
43			`RETURNS`
44			`On success, <<pow>> and <<powf>> return the value calculated.`
45
46			`When the argument values would produce overflow, <<pow>>`
47			`returns <<HUGE_VAL>> and set <<errno>> to <<ERANGE>>. If the`
48			`argument <[x]> passed to <<pow>> or <<powf>> is a negative`
49			`noninteger, and <[y]> is also not an integer, then <<errno>>`
50			`is set to <<EDOM>>. If <[x]> and <[y]> are both 0, then`
51			`<<pow>> and <<powf>> return <<1>>.`
52
53			`You can modify error handling for these functions using <<matherr>>.`
54
55			`PORTABILITY`
56			`<<pow>> is ANSI C. <<powf>> is an extension. */`
57
58			`/*`
59			`* wrapper pow(x,y) return x**y`
60			`*/`
61
62			`#include "fdlibm.h"`
63			`#include <errno.h>`
64
65			`#ifndef _DOUBLE_IS_32BITS`
66
67			`#ifdef __STDC__`
68			`double pow(double x, double y) /* wrapper pow */`
69			`#else`
70			`double pow(x,y) /* wrapper pow */`
71			`double x,y;`
72			`#endif`
73			`{`
74			`#ifdef _IEEE_LIBM`
75			`return __ieee754_pow(x,y);`
76			`#else`
77			`double z;`
78			`#ifndef HUGE_VAL`
79			`#define HUGE_VAL inf`
80			`double inf = 0.0;`
81
82			`SET_HIGH_WORD(inf,0x7ff00000); /* set inf to infinite */`
83			`#endif`
84			`struct exception exc;`
85			`z=__ieee754_pow(x,y);`
86			`if(_LIB_VERSION == _IEEE_\|\| isnan(y)) return z;`
87			`if(isnan(x)) {`
88			`if(y==0.0) {`
89			`/* pow(NaN,0.0) */`
90			`/* error only if _LIB_VERSION == _SVID_ & _XOPEN_ */`
91			`exc.type = DOMAIN;`
92			`exc.name = "pow";`
93			`exc.err = 0;`
94			`exc.arg1 = x;`
95			`exc.arg2 = y;`
96			`exc.retval = 1.0;`
97			`if (_LIB_VERSION == _IEEE_ \|\|`
98			`_LIB_VERSION == _POSIX_) exc.retval = 1.0;`
99			`else if (!matherr(&exc)) {`
100			`errno = EDOM;`
101			`}`
102			`if (exc.err != 0)`
103			`errno = exc.err;`
104			`return exc.retval;`
105			`} else`
106			`return z;`
107			`}`
108			`if(x==0.0){`
109			`if(y==0.0) {`
110			`/* pow(0.0,0.0) */`
111			`/* error only if _LIB_VERSION == _SVID_ */`
112			`exc.type = DOMAIN;`
113			`exc.name = "pow";`
114			`exc.err = 0;`
115			`exc.arg1 = x;`
116			`exc.arg2 = y;`
117			`exc.retval = 0.0;`
118			`if (_LIB_VERSION != _SVID_) exc.retval = 1.0;`
119			`else if (!matherr(&exc)) {`
120			`errno = EDOM;`
121			`}`
122			`if (exc.err != 0)`
123			`errno = exc.err;`
124			`return exc.retval;`
125			`}`
126			`if(finite(y)&&y<0.0) {`
127			`/* 0*neg /`
128			`exc.type = DOMAIN;`
129			`exc.name = "pow";`
130			`exc.err = 0;`
131			`exc.arg1 = x;`
132			`exc.arg2 = y;`
133			`if (_LIB_VERSION == _SVID_)`
134			`exc.retval = 0.0;`
135			`else`
136			`exc.retval = -HUGE_VAL;`
137			`if (_LIB_VERSION == _POSIX_)`
138			`errno = EDOM;`
139			`else if (!matherr(&exc)) {`
140			`errno = EDOM;`
141			`}`
142			`if (exc.err != 0)`
143			`errno = exc.err;`
144			`return exc.retval;`
145			`}`
146			`return z;`
147			`}`
148			`if(!finite(z)) {`
149			`if(finite(x)&&finite(y)) {`
150			`if(isnan(z)) {`
151			`/* neg*non-integral /`
152			`exc.type = DOMAIN;`
153			`exc.name = "pow";`
154			`exc.err = 0;`
155			`exc.arg1 = x;`
156			`exc.arg2 = y;`
157			`if (_LIB_VERSION == _SVID_)`
158			`exc.retval = 0.0;`
159			`else`
160			`exc.retval = 0.0/0.0; /* X/Open allow NaN */`
161			`if (_LIB_VERSION == _POSIX_)`
162			`errno = EDOM;`
163			`else if (!matherr(&exc)) {`
164			`errno = EDOM;`
165			`}`
166			`if (exc.err != 0)`
167			`errno = exc.err;`
168			`return exc.retval;`
169			`} else {`
170			`/* pow(x,y) overflow */`
171			`exc.type = OVERFLOW;`
172			`exc.name = "pow";`
173			`exc.err = 0;`
174			`exc.arg1 = x;`
175			`exc.arg2 = y;`
176			`if (_LIB_VERSION == _SVID_) {`
177			`exc.retval = HUGE;`
178			`y *= 0.5;`
179			`if(x<0.0&&rint(y)!=y) exc.retval = -HUGE;`
180			`} else {`
181			`exc.retval = HUGE_VAL;`
182			`y *= 0.5;`
183			`if(x<0.0&&rint(y)!=y) exc.retval = -HUGE_VAL;`
184			`}`
185			`if (_LIB_VERSION == _POSIX_)`
186			`errno = ERANGE;`
187			`else if (!matherr(&exc)) {`
188			`errno = ERANGE;`
189			`}`
190			`if (exc.err != 0)`
191			`errno = exc.err;`
192			`return exc.retval;`
193			`}`
194			`}`
195			`}`
196			`if(z==0.0&&finite(x)&&finite(y)) {`
197			`/* pow(x,y) underflow */`
198			`exc.type = UNDERFLOW;`
199			`exc.name = "pow";`
200			`exc.err = 0;`
201			`exc.arg1 = x;`
202			`exc.arg2 = y;`
203			`exc.retval = 0.0;`
204			`if (_LIB_VERSION == _POSIX_)`
205			`errno = ERANGE;`
206			`else if (!matherr(&exc)) {`
207			`errno = ERANGE;`
208			`}`
209			`if (exc.err != 0)`
210			`errno = exc.err;`
211			`return exc.retval;`
212			`}`
213			`return z;`
214			`#endif`
215			`}`
216
217			`#endif /* defined(_DOUBLE_IS_32BITS) */`
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