bn_mp_dr_setup.c 985 B

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  1. #include <tommath.h>
  2. #ifdef BN_MP_DR_SETUP_C
  3. /* LibTomMath, multiple-precision integer library -- Tom St Denis
  4. *
  5. * LibTomMath is a library that provides multiple-precision
  6. * integer arithmetic as well as number theoretic functionality.
  7. *
  8. * The library was designed directly after the MPI library by
  9. * Michael Fromberger but has been written from scratch with
  10. * additional optimizations in place.
  11. *
  12. * The library is free for all purposes without any express
  13. * guarantee it works.
  14. *
  15. * Tom St Denis, tomstdenis@gmail.com, http://math.libtomcrypt.com
  16. */
  17. /* determines the setup value */
  18. void mp_dr_setup(mp_int *a, mp_digit *d)
  19. {
  20. /* the casts are required if DIGIT_BIT is one less than
  21. * the number of bits in a mp_digit [e.g. DIGIT_BIT==31]
  22. */
  23. *d = (mp_digit)((((mp_word)1) << ((mp_word)DIGIT_BIT)) -
  24. ((mp_word)a->dp[0]));
  25. }
  26. #endif
  27. /* $Source: /cvs/libtom/libtommath/bn_mp_dr_setup.c,v $ */
  28. /* $Revision: 1.3 $ */
  29. /* $Date: 2006/03/31 14:18:44 $ */