| /* |
| * ==================================================== |
| * 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. |
| * ==================================================== |
| */ |
| |
| |
| /* __ieee754_sinh(x) |
| * Method : |
| * mathematically sinh(x) if defined to be (exp(x)-exp(-x))/2 |
| * 1. Replace x by |x| (sinh(-x) = -sinh(x)). |
| * 2. |
| * E + E/(E+1) |
| * 0 <= x <= 40 : sinh(x) := --------------, E=expm1(x) |
| * 2 |
| * |
| * 40 <= x <= lnovft : sinh(x) := exp(x)/2 |
| * lnovft <= x <= ln2ovft: sinh(x) := exp(x/2)/2 * exp(x/2) |
| * ln2ovft < x : sinh(x) := x*shuge (overflow) |
| * |
| * Special cases: |
| * sinh(x) is |x| if x is +INF, -INF, or NaN. |
| * only sinh(0)=0 is exact for finite x. |
| */ |
| |
| #include <math.h> |
| #include <math_private.h> |
| |
| static const long double one = 1.0, shuge = 1.0e307; |
| |
| long double |
| __ieee754_sinhl(long double x) |
| { |
| long double t,w,h; |
| int64_t ix,jx; |
| double xhi; |
| |
| /* High word of |x|. */ |
| xhi = ldbl_high (x); |
| EXTRACT_WORDS64 (jx, xhi); |
| ix = jx&0x7fffffffffffffffLL; |
| |
| /* x is INF or NaN */ |
| if(ix>=0x7ff0000000000000LL) return x+x; |
| |
| h = 0.5; |
| if (jx<0) h = -h; |
| /* |x| in [0,40], return sign(x)*0.5*(E+E/(E+1))) */ |
| if (ix < 0x4044000000000000LL) { /* |x|<40 */ |
| if (ix<0x3e20000000000000LL) /* |x|<2**-29 */ |
| if(shuge+x>one) return x;/* sinhl(tiny) = tiny with inexact */ |
| t = __expm1l(fabsl(x)); |
| if(ix<0x3ff0000000000000LL) return h*(2.0*t-t*t/(t+one)); |
| w = t/(t+one); |
| return h*(t+w); |
| } |
| |
| /* |x| in [40, log(maxdouble)] return 0.5*exp(|x|) */ |
| if (ix < 0x40862e42fefa39efLL) return h*__ieee754_expl(fabsl(x)); |
| |
| /* |x| in [log(maxdouble), overflowthresold] */ |
| if (ix <= 0x408633ce8fb9f87dLL) { |
| w = __ieee754_expl(0.5*fabsl(x)); |
| t = h*w; |
| return t*w; |
| } |
| |
| /* |x| > overflowthresold, sinh(x) overflow */ |
| return x*shuge; |
| } |
| strong_alias (__ieee754_sinhl, __sinhl_finite) |
