e_scalb.c 1.1 KB

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  1. /* @(#)e_scalb.c 1.3 95/01/18 */
  2. /*
  3. * ====================================================
  4. * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
  5. *
  6. * Developed at SunSoft, 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. /*
  13. * __ieee754_scalb(x, fn) is provide for
  14. * passing various standard test suite. One
  15. * should use scalbn() instead.
  16. */
  17. #include "fdlibm.h"
  18. #ifdef _SCALB_INT
  19. #ifdef __STDC__
  20. double __ieee754_scalb(double x, int fn)
  21. #else
  22. double __ieee754_scalb(x,fn)
  23. double x; int fn;
  24. #endif
  25. #else
  26. #ifdef __STDC__
  27. double __ieee754_scalb(double x, double fn)
  28. #else
  29. double __ieee754_scalb(x,fn)
  30. double x, fn;
  31. #endif
  32. #endif
  33. {
  34. #ifdef _SCALB_INT
  35. return scalbn(x,fn);
  36. #else
  37. if (isnan(x)||isnan(fn)) return x*fn;
  38. if (!finite(fn)) {
  39. if(fn>0.0) return x*fn;
  40. else return x/(-fn);
  41. }
  42. if (rint(fn)!=fn) return (fn-fn)/(fn-fn);
  43. if ( fn > 65000.0) return scalbn(x, 65000);
  44. if (-fn > 65000.0) return scalbn(x,-65000);
  45. return scalbn(x,(int)fn);
  46. #endif
  47. }