/*  slfldiv2.cpp  by K.Tsuru  */
// funstion ID = 235    DRADIX, BRADIX
#ifndef SN_H
#include "sn.h"
#endif
/***************************
SLong and SInteger calsses
It divides by 2.
****************************/
SLong LDiv2(const SLong& n){
    SLong result(n);
    uint rh = n.Head(), rt = n.Tail();
    if(rh == 0){    //only one figure including n = 0
        if( (result.figure[0] = n.figure(0)/2) == 0 ) result.SetSign(0);
        return result;  // n = 0 or 1
    }
    fType rem = 0, u;       // rem : remainder
    fType rdx = n.Radix();
    fType* rv = result.figure.Elements();

#ifndef NDEBUG
result.figure(rh);
#endif

    for(int i = (int)rh; i >= (int)rt; i--) {
        u = rv[i];
        if(rem) u += rdx;
        rem = u & 1;        // rem = 0 or 1
        rv[i] = u / 2;
    }
    if(rem && rt){  rt--;   rv[rt] = rdx/2;     }   // rem = 1
//get figure positions
    while(!rv[rh]) rh--;
    result.aHead = rh;
#ifndef NDEBUG
result.figure(rh);
#endif
//[caution] 24 0000....0001 / 2 ===> 12 0000 ... 0000
    while(!rv[rt]) rt++;
    result.aTail = rt;
    return result;
}