Category : Files from Magazines
Archive   : CUJ0694.ZIP
Filename : HIDEXPF.C

 
Output of file : HIDEXPF.C contained in archive : CUJ0694.ZIP
/* _Expf function */
#define _INCLUDE_XOPEN_SOURCE
#include
#include "xmath.h"

#define hugexp (double)HUGE_EXP

int _Expf(double *px)
{
/* Compute e^(*px), x finite */

double y, g, even;
int xexp, inc;
const static double round[] = {.5, -.5};
#if 0
/* Works OK but slow on many machines */
xexp = *px * M_LOG2E + round[*px < 0];
#else
/* VAX requires -(((short *)px)[1]>>15) */
xexp = *px * M_LOG2E + round[((unsigned int *) px)[_D0] >> 31];
#endif
g = *px - xexp * M_LN2;
g *= (y = g * g) + 60.09114349;
even = y * 12.01517514 + 120.18228722;
*px = (even + g) / (even - g);
/* Limit exponent to wide enough range to cause over/underflow upon
* conversion to float without getting into double over/underflow */
inc = g > 0;
if (xexp > DBL_MAX_EXP - inc) xexp = DBL_MAX_EXP - inc;
if (xexp < DBL_MIN_EXP - inc) xexp = DBL_MIN_EXP - inc;
((unsigned long *) px)[_D0] += xexp << _DOFF; /* scale by 2^xexp */
return xexp + inc; /* exponent = ceil(log2(*px)) */
}


  3 Responses to “Category : Files from Magazines
Archive   : CUJ0694.ZIP
Filename : HIDEXPF.C
”

  1. Daniel says:
    January 27, 2013 at 3:59 pm

    Very nice! Thank you for this wonderful archive. I wonder why I found it only now. Long live the BBS file archives!

  2. Joshie says:
    March 18, 2014 at 4:57 pm

    This is so awesome! 😀 I’d be cool if you could download an entire archive of this at once, though.

  3. DiskingRound says:
    January 14, 2015 at 10:57 pm

    But one thing that puzzles me is the “mtswslnkmcjklsdlsbdmMICROSOFT” string. There is an article about it here. It is definitely worth a read: http://www.os2museum.com/wp/mtswslnk/