e_scalb.c 1.3 KB

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  1. /* @(#)e_scalb.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: e_scalb.c,v 1.6 1995/05/10 20:46:09 jtc Exp $";
  14. #endif
  15. /*
  16. * __ieee754_scalb(x, fn) is provide for
  17. * passing various standard test suite. One
  18. * should use scalbn() instead.
  19. */
  20. #include "math.h"
  21. #include "math_private.h"
  22. #ifdef _SCALB_INT
  23. #ifdef __STDC__
  24. double __ieee754_scalb(double x, int fn)
  25. #else
  26. double __ieee754_scalb(x,fn)
  27. double x; int fn;
  28. #endif
  29. #else
  30. #ifdef __STDC__
  31. double __ieee754_scalb(double x, double fn)
  32. #else
  33. double __ieee754_scalb(x,fn)
  34. double x, fn;
  35. #endif
  36. #endif
  37. {
  38. #ifdef _SCALB_INT
  39. return scalbn(x,fn);
  40. #else
  41. if (isnan(x)||isnan(fn)) return x*fn;
  42. if (!finite(fn)) {
  43. if(fn>0.0) return x*fn;
  44. else return x/(-fn);
  45. }
  46. if (rint(fn)!=fn) return (fn-fn)/(fn-fn);
  47. if ( fn > 65000.0) return scalbn(x, 65000);
  48. if (-fn > 65000.0) return scalbn(x,-65000);
  49. return scalbn(x,(int)fn);
  50. #endif
  51. }