o1 |= 1 << 1 /* mb[5] */
		}

	case 57: /* slw $sh,[s,]a -> rlwinm ... */
		v := c.regoff(&p.From)

		r := int(p.Reg)
		if r == 0 {
			r = int(p.To.Reg)
		}

		/*
			 * Let user (gs) shoot himself in the foot.
			 * qc has already complained.
			 *
			if(v < 0 || v > 31)
				ctxt->diag("illegal shift %ld\n%v", v, p);
		*/
		if v < 0 {
			v = 0
		} else if v > 32 {