Subversion Repositories planix.SVN

#include "os.h"
#include <mp.h>
#include "dat.h"

#define VLDIGITS (sizeof(vlong)/sizeof(mpdigit))

/*
 *  this code assumes that a vlong is an integral number of
 *  mpdigits long.
 */
mpint*
vtomp(vlong v, mpint *b)
{
        int s;
        uvlong uv;

        if(b == nil)
                b = mpnew(VLDIGITS*sizeof(mpdigit));
        else
                mpbits(b, VLDIGITS*sizeof(mpdigit));
        mpassign(mpzero, b);
        if(v == 0)
                return b;
        if(v < 0){
                b->sign = -1;
                uv = -v;
        } else
                uv = v;
        for(s = 0; s < VLDIGITS && uv != 0; s++){
                b->p[s] = uv;
                uv >>= sizeof(mpdigit)*8;
        }
        b->top = s;
        return b;
}

vlong
mptov(mpint *b)
{
        uvlong v;
        int s;

        if(b->top == 0)
                return (vlong) 0;

        mpnorm(b);
        if(b->top > VLDIGITS){
                if(b->sign > 0)
                        return (vlong)MAXVLONG;
                else
                        return (vlong)MINVLONG;
        }

        v = (uvlong) 0;
        for(s = 0; s < b->top; s++)
                v |= b->p[s]<<(s*sizeof(mpdigit)*8);

        if(b->sign > 0){
                if(v > MAXVLONG)
                        v = MAXVLONG;
        } else {
                if(v > MINVLONG)
                        v = MINVLONG;
                else
                        v = -(vlong)v;
        }

        return (vlong)v;
}