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Diffstat (limited to 'newlib/libm/math/w_jn.c')
| -rw-r--r-- | newlib/libm/math/w_jn.c | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/newlib/libm/math/w_jn.c b/newlib/libm/math/w_jn.c new file mode 100644 index 00000000000..6cadc9a0104 --- /dev/null +++ b/newlib/libm/math/w_jn.c @@ -0,0 +1,141 @@ + +/* @(#)w_jn.c 5.1 93/09/24 */ +/* + * ==================================================== + * 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. + * ==================================================== + */ + +/* + * wrapper jn(int n, double x), yn(int n, double x) + * floating point Bessel's function of the 1st and 2nd kind + * of order n + * + * Special cases: + * y0(0)=y1(0)=yn(n,0) = -inf with division by zero signal; + * y0(-ve)=y1(-ve)=yn(n,-ve) are NaN with invalid signal. + * Note 2. About jn(n,x), yn(n,x) + * For n=0, j0(x) is called, + * for n=1, j1(x) is called, + * for n<x, forward recursion us used starting + * from values of j0(x) and j1(x). + * for n>x, a continued fraction approximation to + * j(n,x)/j(n-1,x) is evaluated and then backward + * recursion is used starting from a supposed value + * for j(n,x). The resulting value of j(0,x) is + * compared with the actual value to correct the + * supposed value of j(n,x). + * + * yn(n,x) is similar in all respects, except + * that forward recursion is used for all + * values of n>1. + * + */ + +#include "fdlibm.h" +#include <errno.h> + +#ifndef _DOUBLE_IS_32BITS + +#ifdef __STDC__ + double jn(int n, double x) /* wrapper jn */ +#else + double jn(n,x) /* wrapper jn */ + double x; int n; +#endif +{ +#ifdef _IEEE_LIBM + return __ieee754_jn(n,x); +#else + double z; + struct exception exc; + z = __ieee754_jn(n,x); + if(_LIB_VERSION == _IEEE_ || isnan(x) ) return z; + if(fabs(x)>X_TLOSS) { + /* jn(|x|>X_TLOSS) */ + exc.type = TLOSS; + exc.name = "jn"; + exc.err = 0; + exc.arg1 = n; + exc.arg2 = x; + 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; + } else + return z; +#endif +} + +#ifdef __STDC__ + double yn(int n, double x) /* wrapper yn */ +#else + double yn(n,x) /* wrapper yn */ + double x; int n; +#endif +{ +#ifdef _IEEE_LIBM + return __ieee754_yn(n,x); +#else + double z; + struct exception exc; + z = __ieee754_yn(n,x); + if(_LIB_VERSION == _IEEE_ || isnan(x) ) return z; + if(x <= 0.0){ + /* yn(n,0) = -inf or yn(x<0) = NaN */ +#ifndef HUGE_VAL +#define HUGE_VAL inf + double inf = 0.0; + + SET_HIGH_WORD(inf,0x7ff00000); /* set inf to infinite */ +#endif + exc.type = DOMAIN; /* should be SING for IEEE */ + exc.name = "yn"; + exc.err = 0; + exc.arg1 = n; + exc.arg2 = x; + if (_LIB_VERSION == _SVID_) + exc.retval = -HUGE; + 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; + } + if(x>X_TLOSS) { + /* yn(x>X_TLOSS) */ + exc.type = TLOSS; + exc.name = "yn"; + exc.err = 0; + exc.arg1 = n; + exc.arg2 = x; + 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; + } else + return z; +#endif +} + +#endif /* defined(_DOUBLE_IS_32BITS) */ |