diff options
Diffstat (limited to 'src/complex/ccosh.c')
| -rw-r--r-- | src/complex/ccosh.c | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/src/complex/ccosh.c b/src/complex/ccosh.c new file mode 100644 index 00000000..81f29432 --- /dev/null +++ b/src/complex/ccosh.c @@ -0,0 +1,140 @@ +/* origin: FreeBSD /usr/src/lib/msun/src/s_ccosh.c */ +/*- + * Copyright (c) 2005 Bruce D. Evans and Steven G. Kargl + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice unmodified, this list of conditions, and the following + * disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ +/* + * Hyperbolic cosine of a complex argument z = x + i y. + * + * cosh(z) = cosh(x+iy) + * = cosh(x) cos(y) + i sinh(x) sin(y). + * + * Exceptional values are noted in the comments within the source code. + * These values and the return value were taken from n1124.pdf. + */ + +#include "libm.h" + +static const double huge = 0x1p1023; + +double complex ccosh(double complex z) +{ + double x, y, h; + int32_t hx, hy, ix, iy, lx, ly; + + x = creal(z); + y = cimag(z); + + EXTRACT_WORDS(hx, lx, x); + EXTRACT_WORDS(hy, ly, y); + + ix = 0x7fffffff & hx; + iy = 0x7fffffff & hy; + + /* Handle the nearly-non-exceptional cases where x and y are finite. */ + if (ix < 0x7ff00000 && iy < 0x7ff00000) { + if ((iy | ly) == 0) + return cpack(cosh(x), x * y); + if (ix < 0x40360000) /* small x: normal case */ + return cpack(cosh(x) * cos(y), sinh(x) * sin(y)); + + /* |x| >= 22, so cosh(x) ~= exp(|x|) */ + if (ix < 0x40862e42) { + /* x < 710: exp(|x|) won't overflow */ + h = exp(fabs(x)) * 0.5; + return cpack(h * cos(y), copysign(h, x) * sin(y)); + } else if (ix < 0x4096bbaa) { + /* x < 1455: scale to avoid overflow */ + z = __ldexp_cexp(cpack(fabs(x), y), -1); + return cpack(creal(z), cimag(z) * copysign(1, x)); + } else { + /* x >= 1455: the result always overflows */ + h = huge * x; + return cpack(h * h * cos(y), h * sin(y)); + } + } + + /* + * cosh(+-0 +- I Inf) = dNaN + I sign(d(+-0, dNaN))0. + * The sign of 0 in the result is unspecified. Choice = normally + * the same as dNaN. Raise the invalid floating-point exception. + * + * cosh(+-0 +- I NaN) = d(NaN) + I sign(d(+-0, NaN))0. + * The sign of 0 in the result is unspecified. Choice = normally + * the same as d(NaN). + */ + if ((ix | lx) == 0 && iy >= 0x7ff00000) + return cpack(y - y, copysign(0, x * (y - y))); + + /* + * cosh(+-Inf +- I 0) = +Inf + I (+-)(+-)0. + * + * cosh(NaN +- I 0) = d(NaN) + I sign(d(NaN, +-0))0. + * The sign of 0 in the result is unspecified. + */ + if ((iy | ly) == 0 && ix >= 0x7ff00000) { + if (((hx & 0xfffff) | lx) == 0) + return cpack(x * x, copysign(0, x) * y); + return cpack(x * x, copysign(0, (x + x) * y)); + } + + /* + * cosh(x +- I Inf) = dNaN + I dNaN. + * Raise the invalid floating-point exception for finite nonzero x. + * + * cosh(x + I NaN) = d(NaN) + I d(NaN). + * Optionally raises the invalid floating-point exception for finite + * nonzero x. Choice = don't raise (except for signaling NaNs). + */ + if (ix < 0x7ff00000 && iy >= 0x7ff00000) + return cpack(y - y, x * (y - y)); + + /* + * cosh(+-Inf + I NaN) = +Inf + I d(NaN). + * + * cosh(+-Inf +- I Inf) = +Inf + I dNaN. + * The sign of Inf in the result is unspecified. Choice = always +. + * Raise the invalid floating-point exception. + * + * cosh(+-Inf + I y) = +Inf cos(y) +- I Inf sin(y) + */ + if (ix >= 0x7ff00000 && ((hx & 0xfffff) | lx) == 0) { + if (iy >= 0x7ff00000) + return cpack(x * x, x * (y - y)); + return cpack((x * x) * cos(y), x * sin(y)); + } + + /* + * cosh(NaN + I NaN) = d(NaN) + I d(NaN). + * + * cosh(NaN +- I Inf) = d(NaN) + I d(NaN). + * Optionally raises the invalid floating-point exception. + * Choice = raise. + * + * cosh(NaN + I y) = d(NaN) + I d(NaN). + * Optionally raises the invalid floating-point exception for finite + * nonzero y. Choice = don't raise (except for signaling NaNs). + */ + return cpack((x * x) * (y - y), (x + x) * (y - y)); +} |