/* Opcode 6, IOT */
case 030:case 031:case 032:case 033:			/* IOT */
	if (UF) {					/* privileged? */
		int_req = int_req | INT_UF;
		break;  }
	device = (IR >> 3) & 077;			/* device = IR<3:8> */
	pulse = IR & 07;				/* pulse = IR<9:11> */
	iot_data = LAC & 07777;				/* AC unchanged */
	switch (device) {				/* decode IR<3:8> */
	case 0:						/* CPU control */
		switch (pulse) {			/* decode IR<9:11> */
		case 0:					/* SKON */
		case 1:					/* ION */
		case 2:					/* IOF */
		case 3:					/* SRQ */
		case 4:					/* GTF */
		case 5:					/* RTF */
		case 6:					/* SGT */
		case 7:					/* CAF */
/* IOT, continued: memory extension */
	case 020:case 021:case 022:case 023:
	case 024:case 025:case 026:case 027:		/* memory extension */
		switch (pulse) {			/* decode IR<9:11> */
		case 1: 				/* CDF */
		case 2:					/* CIF */
		case 3:					/* CDF CIF */
		case 4:
			case 1:				/* RDF */
			case 2:				/* RIF */
			case 3:				/* RIB */
			case 4:				/* RMF */
			case 5:				/* SINT */
			case 6:				/* CUF */
			case 7:				/* SUF */
/* IOT, other special cases */
	case 010:					/* power fail */
		switch (pulse) {			/* decode IR<9:11> */
		case 1:					/* SBE */
		case 2: 				/* SPL */
		case 3: 				/* CAL */
/* IOT, I/O devices */
	case 1:						/* PTR */
	case 2:						/* PTP */
	case 3:						/* TTI */
	case 4: 					/* TTO */
	case 013:					/* CLK */
	case 060:					/* DF32/RF08 */
	case 061:
	case 062:
	case 064:
	case 066:					/* LPT */
	case 070:					/* TM8E */
	case 071:
	case 072:
	case 074:					/* RK8E */
	case 075:					/* RX8E */
	case 076:					/* TC01/TC08 */
	case 077: