text: #include "tommath_private.h"
  #ifdef BN_MP_RSHD_C
  /* LibTomMath, multiple-precision integer library -- Tom St Denis
   *
   * LibTomMath is a library that provides multiple-precision
   * integer arithmetic as well as number theoretic functionality.
   *
   * The library was designed directly after the MPI library by
   * Michael Fromberger but has been written from scratch with
   * additional optimizations in place.
   *
   * The library is free for all purposes without any express
   * guarantee it works.
   */
  
  /* shift right a certain amount of digits */
  void mp_rshd(mp_int *a, int b)
  {
     int     x;
  
     /* if b <= 0 then ignore it */
     if (b <= 0) {
        return;
     }
  
     /* if b > used then simply zero it and return */
     if (a->used <= b) {
        mp_zero(a);
        return;
     }
  
     {
        mp_digit *bottom, *top;
  
        /* shift the digits down */
  
        /* bottom */
        bottom = a->dp;
  
        /* top [offset into digits] */
        top = a->dp + b;
  
        /* this is implemented as a sliding window where
         * the window is b-digits long and digits from
         * the top of the window are copied to the bottom
         *
         * e.g.
  
         b-2 | b-1 | b0 | b1 | b2 | ... | bb |   ---->
                     /\                   |      ---->
                      \-------------------/      ---->
         */
        for (x = 0; x < (a->used - b); x++) {
           *bottom++ = *top++;
        }
  
        /* zero the top digits */
        for (; x < a->used; x++) {
           *bottom++ = 0;
        }
     }
  
     /* remove excess digits */
     a->used -= b;
  }
  #endif
  
  /* ref:         $Format:%D$ */
  /* git commit:  $Format:%H$ */
  /* commit time: $Format:%ai$ */
  