| 0,0 → 1,87 |
|---|
| /* Copyright (C) 1994 DJ Delorie, see COPYING.DJ for details */ |
| /* @(#)e_sinh.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. |
| * ==================================================== |
| */ |
| |
| #if defined(LIBM_SCCS) && !defined(lint) |
| static char rcsid[] = "$Id: e_sinh.c,v 1.5 1994/08/18 23:06:03 jtc Exp $"; |
| #endif |
| |
| /* __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 <= 22 : sinh(x) := --------------, E=expm1(x) |
| * 2 |
| * |
| * 22 <= 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" |
| |
| #ifdef __STDC__ |
| static const double one = 1.0, shuge = 1.0e307; |
| #else |
| static double one = 1.0, shuge = 1.0e307; |
| #endif |
| |
| #ifdef __STDC__ |
| double __ieee754_sinh(double x) |
| #else |
| double __ieee754_sinh(x) |
| double x; |
| #endif |
| { |
| double t,w,h; |
| int32_t ix,jx; |
| u_int32_t lx; |
| |
| /* High word of |x|. */ |
| GET_HIGH_WORD(jx,x); |
| ix = jx&0x7fffffff; |
| |
| /* x is INF or NaN */ |
| if(ix>=0x7ff00000) return x+x; |
| |
| h = 0.5; |
| if (jx<0) h = -h; |
| /* |x| in [0,22], return sign(x)*0.5*(E+E/(E+1))) */ |
| if (ix < 0x40360000) { /* |x|<22 */ |
| if (ix<0x3e300000) /* |x|<2**-28 */ |
| if(shuge+x>one) return x;/* sinh(tiny) = tiny with inexact */ |
| t = expm1(fabs(x)); |
| if(ix<0x3ff00000) return h*(2.0*t-t*t/(t+one)); |
| return h*(t+t/(t+one)); |
| } |
| |
| /* |x| in [22, log(maxdouble)] return 0.5*exp(|x|) */ |
| if (ix < 0x40862E42) return h*__ieee754_exp(fabs(x)); |
| |
| /* |x| in [log(maxdouble), overflowthresold] */ |
| GET_LOW_WORD(lx,x); |
| if (ix<0x408633CE || (ix==0x408633ce)&&(lx<=(u_int32_t)0x8fb9f87d)) { |
| w = __ieee754_exp(0.5*fabs(x)); |
| t = h*w; |
| return t*w; |
| } |
| |
| /* |x| > overflowthresold, sinh(x) overflow */ |
| return x*shuge; |
| } |