shl(register digit *p, register int len, register int sh)
shl(p, len, sh) register digit *p; register int len; register int sh;
shl(register digit *p, register int len, register int sh){	register int i;	for (i = 0; i < len; i++)		p[i] = LHALF(p[i] << sh) | (p[i + 1] >> (HALF_BITS - sh));	p[i] = LHALF(p[i] << sh);}