normalize( a )
	mp a;

	{int cy, i, la;
	la = length(a);
	start:
	cy = 0;
	for ( i=1; i<la; i++ )	{
		cy = (a[i] += cy) / BASE;
		a[i] -= cy*BASE;
		if (a[i]<0)	{a[i] += BASE;	cy--;}
		}
	while (cy>0)	{
		a[i++] = cy%BASE;
		cy /= BASE;}
	if (cy<0)	{
		a[la-1] += cy*BASE;
		for (i=1; i<la; i++)	a[i] = -a[i];
		storesign( a, sign(a)==POS ? NEG : POS );
		goto start;
		}
	while (a[i-1]==0 && i>2) i--;
	storelength( a, i );
	if ( i==2 && a[1]==0 )	storesign( a, POS );
	};