static inline BYTE io_read(io_source_list_t *list, WORD addr)
{
io_source_list_t *current = list->next;
int io_source_counter = 0;
BYTE realval = 0;
BYTE retval = 0;
unsigned int lowest_order = 0xffffffff;
vicii_handle_pending_alarms_external(0);
while (current) {
if (current->device->read != NULL) {
if ((addr >= current->device->start_address) && (addr <= current->device->end_address)) {
retval = current->device->read((WORD)(addr & current->device->address_mask));
if (current->device->io_source_valid) {
if (current->device->io_source_prio == IO_PRIO_HIGH) {
return retval;
}
if (io_source_collision_handling == IO_COLLISION_METHOD_DETACH_LAST) {
if (current->device->order < lowest_order) {
lowest_order = current->device->order;
realval = retval;
}
}
if (io_source_collision_handling == IO_COLLISION_METHOD_AND_WIRES) {
realval &= retval;
}
if (current->device->io_source_prio != IO_PRIO_LOW) {
io_source_counter++;
}
}
}
}
current = current->next;
}
if (io_source_counter == 0) {
return vicii_read_phi1();
}
if (io_source_counter == 1) {
return retval;
}
if (io_source_collision_handling == IO_COLLISION_METHOD_DETACH_ALL) {
io_source_msg_detach_all(addr, io_source_counter, list);
return vicii_read_phi1();
}
if (io_source_collision_handling == IO_COLLISION_METHOD_DETACH_LAST) {
io_source_msg_detach_last(addr, io_source_counter, list, lowest_order);
return realval;
}
if (io_source_collision_handling == IO_COLLISION_METHOD_AND_WIRES) {
io_source_log_collisions(addr, io_source_counter, list);
return realval;
}
return vicii_read_phi1();
}
static inline BYTE io_read(io_source_list_t *list, WORD addr)
{
io_source_list_t *current = list->next;
int io_source_counter = 0;
int io_source_valid = 0;
BYTE realval = 0;
BYTE retval = 0;
BYTE firstval = 0;
unsigned int lowest_order = 0xffffffff;
vicii_handle_pending_alarms_external(0);
while (current) {
if (current->device->read != NULL) {
if ((addr >= current->device->start_address) && (addr <= current->device->end_address)) {
retval = current->device->read((WORD)(addr & current->device->address_mask));
if (current->device->io_source_valid) {
/* high prio always overrides others, return immediatly */
if (current->device->io_source_prio == IO_PRIO_HIGH) {
return retval;
}
if (io_source_valid == 0) {
/* on first valid read, initialize intermediate values */
firstval = realval = retval;
lowest_order = current->device->order;
/* do not count low prio, as it will always be overridden by others */
if (current->device->io_source_prio != IO_PRIO_LOW) {
io_source_counter++;
}
io_source_valid = 1;
} else {
/* ignore low prio reads when a real value is present already */
if (current->device->io_source_prio == IO_PRIO_LOW) {
retval = realval;
}
if (io_source_collision_handling == IO_COLLISION_METHOD_DETACH_LAST) {
if (current->device->order < lowest_order) {
lowest_order = current->device->order;
realval = retval;
}
} else if (io_source_collision_handling == IO_COLLISION_METHOD_AND_WIRES) {
realval &= retval;
}
/* do not count low prio, as it will always be overridden by others */
if (current->device->io_source_prio != IO_PRIO_LOW) {
/* if the nth read returns the same as the first read don't see it as a conflict */
if (retval != firstval) {
io_source_counter++;
}
}
}
}
}
}
current = current->next;
}
/* no valid I/O source was read, return phi1 */
if (io_source_valid == 0) {
return vicii_read_phi1();
}
/* only one valid I/O source was read, return value */
if (!(io_source_counter > 1)) {
return retval;
}
/* more than one I/O source was read, handle collision */
if (io_source_collision_handling == IO_COLLISION_METHOD_DETACH_ALL) {
io_source_msg_detach_all(addr, io_source_counter, list);
return vicii_read_phi1();
} else if (io_source_collision_handling == IO_COLLISION_METHOD_DETACH_LAST) {
io_source_msg_detach_last(addr, io_source_counter, list, lowest_order);
return realval;
} else if (io_source_collision_handling == IO_COLLISION_METHOD_AND_WIRES) {
io_source_log_collisions(addr, io_source_counter, list);
return realval;
}
return vicii_read_phi1();
}
