diff options
author | Andreas Jaeger <aj@suse.de> | 2001-06-04 08:31:38 +0000 |
---|---|---|
committer | Andreas Jaeger <aj@suse.de> | 2001-06-04 08:31:38 +0000 |
commit | 94a38ea3c432919dc1289957025f6fc5b2e3d7a7 (patch) | |
tree | 9f80bf6bc1d43497bf2acd4631f2c9655354351e /sysdeps | |
parent | eaeeb1eb428500658671f12aa4938543396ab7b9 (diff) | |
download | glibc-94a38ea3c432919dc1289957025f6fc5b2e3d7a7.tar glibc-94a38ea3c432919dc1289957025f6fc5b2e3d7a7.tar.gz glibc-94a38ea3c432919dc1289957025f6fc5b2e3d7a7.tar.bz2 glibc-94a38ea3c432919dc1289957025f6fc5b2e3d7a7.zip |
128 bit sinh implementation.
Diffstat (limited to 'sysdeps')
-rw-r--r-- | sysdeps/ieee754/ldbl-128/e_sinhl.c | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/sysdeps/ieee754/ldbl-128/e_sinhl.c b/sysdeps/ieee754/ldbl-128/e_sinhl.c new file mode 100644 index 0000000000..71e283d2de --- /dev/null +++ b/sysdeps/ieee754/ldbl-128/e_sinhl.c @@ -0,0 +1,105 @@ +/* e_sinhl.c -- long double version of e_sinh.c. + * Conversion to long double by Ulrich Drepper, + * Cygnus Support, drepper@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. + * ==================================================== + */ + +/* Changes for 128-bit long double contributed by + Stephen L. Moshier <moshier@na-net.ornl.gov> */ + +/* __ieee754_sinhl(x) + * Method : + * mathematically sinh(x) if defined to be (exp(x)-exp(-x))/2 + * 1. Replace x by |x| (sinhl(-x) = -sinhl(x)). + * 2. + * E + E/(E+1) + * 0 <= x <= 25 : sinhl(x) := --------------, E=expm1l(x) + * 2 + * + * 25 <= x <= lnovft : sinhl(x) := expl(x)/2 + * lnovft <= x <= ln2ovft: sinhl(x) := expl(x/2)/2 * expl(x/2) + * ln2ovft < x : sinhl(x) := x*shuge (overflow) + * + * Special cases: + * sinhl(x) is |x| if x is +INF, -INF, or NaN. + * only sinhl(0)=0 is exact for finite x. + */ + +#include "math.h" +#include "math_private.h" + +#ifdef __STDC__ +static const long double one = 1.0, shuge = 1.0e4931L, +ovf_thresh = 1.1357216553474703894801348310092223067821E4L; +#else +static long double one = 1.0, shuge = 1.0e4931L, +ovf_thresh = 1.1357216553474703894801348310092223067821E4L; +#endif + +#ifdef __STDC__ +long double +__ieee754_sinhl (long double x) +#else +long double +__ieee754_sinhl (x) + long double x; +#endif +{ + long double t, w, h; + u_int32_t jx, ix; + ieee854_long_double_shape_type u; + + /* Words of |x|. */ + u.value = x; + jx = u.parts32.w0; + ix = jx & 0x7fffffff; + + /* x is INF or NaN */ + if (ix >= 0x7fff0000) + return x + x; + + h = 0.5; + if (jx & 0x80000000) + h = -h; + + /* Absolute value of x. */ + u.parts32.w0 = ix; + + /* |x| in [0,40], return sign(x)*0.5*(E+E/(E+1))) */ + if (ix <= 0x40044000) + { + if (ix < 0x3fc60000) /* |x| < 2^-57 */ + if (shuge + x > one) + return x; /* sinh(tiny) = tiny with inexact */ + t = __expm1l (u.value); + if (ix < 0x3fff0000) + return h * (2.0 * t - t * t / (t + one)); + return h * (t + t / (t + one)); + } + + /* |x| in [40, log(maxdouble)] return 0.5*exp(|x|) */ + if (ix <= 0x400c62e3) /* 11356.375 */ + return h * __ieee754_expl (u.value); + + /* |x| in [log(maxdouble), overflowthreshold] + Overflow threshold is log(2 * maxdouble). */ + if (u.value <= ovf_thresh) + { + w = __ieee754_expl (0.5 * u.value); + t = h * w; + return t * w; + } + + /* |x| > overflowthreshold, sinhl(x) overflow */ + return x * shuge; +} |