w_exp.c 1.3 KB

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  1. /* @(#)w_exp.c 5.1 93/09/24 */
  2. /*
  3. * ====================================================
  4. * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
  5. *
  6. * Developed at SunPro, a Sun Microsystems, Inc. business.
  7. * Permission to use, copy, modify, and distribute this
  8. * software is freely granted, provided that this notice
  9. * is preserved.
  10. * ====================================================
  11. */
  12. #if defined(LIBM_SCCS) && !defined(lint)
  13. static char rcsid[] = "$NetBSD: w_exp.c,v 1.6 1995/05/10 20:48:51 jtc Exp $";
  14. #endif
  15. /*
  16. * wrapper exp(x)
  17. */
  18. #include "math.h"
  19. #include "math_private.h"
  20. #ifdef __STDC__
  21. static const double
  22. #else
  23. static double
  24. #endif
  25. o_threshold= 7.09782712893383973096e+02, /* 0x40862E42, 0xFEFA39EF */
  26. u_threshold= -7.45133219101941108420e+02; /* 0xc0874910, 0xD52D3051 */
  27. #ifdef __STDC__
  28. double exp(double x) /* wrapper exp */
  29. #else
  30. double exp(x) /* wrapper exp */
  31. double x;
  32. #endif
  33. {
  34. #ifdef _IEEE_LIBM
  35. return __ieee754_exp(x);
  36. #else
  37. double z;
  38. z = __ieee754_exp(x);
  39. if(_LIB_VERSION == _IEEE_) return z;
  40. if(finite(x)) {
  41. if(x>o_threshold)
  42. return __kernel_standard(x,x,6); /* exp overflow */
  43. else if(x<u_threshold)
  44. return __kernel_standard(x,x,7); /* exp underflow */
  45. }
  46. return z;
  47. #endif
  48. }
  49. libm_hidden_def(exp)