s_isnan.c 698 B

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  1. /*
  2. * ====================================================
  3. * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
  4. *
  5. * Developed at SunPro, a Sun Microsystems, Inc. business.
  6. * Permission to use, copy, modify, and distribute this
  7. * software is freely granted, provided that this notice
  8. * is preserved.
  9. * ====================================================
  10. */
  11. /*
  12. * isnan(x) returns 1 is x is nan, else 0;
  13. * no branching!
  14. */
  15. #include "math.h"
  16. #include "math_private.h"
  17. int __isnan(double x)
  18. {
  19. int32_t hx,lx;
  20. EXTRACT_WORDS(hx,lx,x);
  21. hx &= 0x7fffffff;
  22. hx |= (u_int32_t)(lx|(-lx))>>31;
  23. hx = 0x7ff00000 - hx;
  24. return (int)(((u_int32_t)hx)>>31);
  25. }
  26. libm_hidden_def(__isnan)