+
+ return NULL;
+}
+
+/* Record that data is available for a queued command. Returns zero if
+ the device was reselected, nonzero if the IO is deferred. */
+static int lsi_queue_tag(LSIState *s, uint32_t tag, uint32_t arg)
+{
+ lsi_request *p;
+
+ p = lsi_find_by_tag(s, tag);
+ if (!p) {
+ BADF("IO with unknown tag %d\n", tag);
+ return 1;
+ }
+
+ if (p->pending) {
+ BADF("Multiple IO pending for tag %d\n", tag);
+ }
+ p->pending = arg;
+ /* Reselect if waiting for it, or if reselection triggers an IRQ
+ and the bus is free.
+ Since no interrupt stacking is implemented in the emulation, it
+ is also required that there are no pending interrupts waiting
+ for service from the device driver. */
+ if (s->waiting == 1 ||
+ (lsi_irq_on_rsl(s) && !(s->scntl1 & LSI_SCNTL1_CON) &&
+ !(s->istat0 & (LSI_ISTAT0_SIP | LSI_ISTAT0_DIP)))) {
+ /* Reselect device. */
+ lsi_reselect(s, p);
+ return 0;
+ } else {
+ DPRINTF("Queueing IO tag=0x%x\n", tag);
+ p->pending = arg;
+ return 1;
+ }