/**
* Read data from the specific position indicated by the disk id and sector id.
* @param disk_id: Indicates which disk to read from.
* @param sector: Indicates which sector to read from.
* @param buffer: The buffer to hold the data.
*/
void os_disk_read(INT32 disk_id, INT32 sector, char *buffer)
{
INT32 status;
int result;
write_to_memory(Z502DiskSetID, &disk_id);
read_from_memory(Z502DiskStatus, &status);
// Disk hasn't been used - should be free
if (status == DEVICE_FREE)
{
write_to_memory(Z502DiskSetSector, §or);
write_to_memory(Z502DiskSetBuffer, (INT32 *) buffer);
status = 0; // Specify a read
write_to_memory(Z502DiskSetAction, &status);
status = 0; // Must be set to 0
write_to_memory(Z502DiskStart, &status);
CurrentPCB->disk_id = disk_id;
CurrentPCB->operation = -1;
get_data_lock(SUSPEND_QUEUE_LOCK);
result = add_to_suspend_queue(CurrentPCB);
release_data_lock(SUSPEND_QUEUE_LOCK);
if (result)
{
CurrentPCB->suspend = TRUE;
print_scheduling_info(ACTION_NAME_READ, CurrentPCB, NORMAL_INFO);
}
else
{
error_message("add_to_suspend_queue");
shut_down();
}
os_dispatcher();
}
else if (status == DEVICE_IN_USE)
{
CurrentPCB->disk_id = disk_id;
CurrentPCB->operation = READ_ONE;
CurrentPCB->disk = disk_id;
CurrentPCB->sector = sector;
CurrentPCB->disk_data = (DISK_DATA *) buffer;
get_data_lock(SUSPEND_QUEUE_LOCK);
result = add_to_suspend_queue(CurrentPCB);
release_data_lock(SUSPEND_QUEUE_LOCK);
if (result)
{
CurrentPCB->suspend = TRUE;
print_scheduling_info(ACTION_NAME_READ, CurrentPCB, NORMAL_INFO);
}
else
{
error_message("add_to_suspend_queue");
shut_down();
}
os_dispatcher();
}
}
char *dpth_mk(struct dpth *dpth)
{
static char save_path[32];
static struct lock *lock=NULL;
while(1)
{
snprintf(save_path, sizeof(save_path), "%04X/%04X/%04X/%04X",
dpth->prim, dpth->seco, dpth->tert, dpth->sig);
if(!dpth->need_data_lock) return save_path;
if(!lock && !(lock=lock_alloc())) goto error;
if(get_data_lock(lock, dpth, save_path)) goto error;
switch(lock->status)
{
case GET_LOCK_GOT: break;
case GET_LOCK_NOT_GOT:
// Increment and try again.
if(dpth_incr(dpth)) goto error;
continue;
case GET_LOCK_ERROR:
default:
goto error;
}
dpth->need_data_lock=0; // Got it.
if(add_lock_to_list(dpth, lock, save_path)) goto error;
lock=NULL;
return save_path;
}
error:
lock_free(&lock);
return NULL;
}
/**
* Write data into the specific position indicated by the disk id and sector id.
* @param disk_id: Indicates which disk to write to.
* @param sector: Indicates which sector to write to.
* @param buffer: The data needs to be written.
*/
void os_disk_write(INT32 disk_id, INT32 sector, char *buffer)
{
INT32 status;
int result;
/* Do the hardware call to put data on disk */
write_to_memory(Z502DiskSetID, &disk_id);
read_from_memory(Z502DiskStatus, &status);
// If the disk is free, indicates success in writing.
if (status == DEVICE_FREE)
{
write_to_memory(Z502DiskSetSector, §or);
write_to_memory(Z502DiskSetBuffer, (INT32 *) buffer);
status = 1; // Specify a write
write_to_memory(Z502DiskSetAction, &status);
status = 0; // Must be set to 0
write_to_memory(Z502DiskStart, &status);
CurrentPCB->disk_id = disk_id;
CurrentPCB->operation = -1;
get_data_lock(SUSPEND_QUEUE_LOCK);
result = add_to_suspend_queue(CurrentPCB);
release_data_lock(SUSPEND_QUEUE_LOCK);
if (result)
{
CurrentPCB->suspend = TRUE;
print_scheduling_info(ACTION_NAME_SUSPEND, CurrentPCB, NORMAL_INFO);
}
else
{
error_message("add_to_suspend_queue");
shut_down();
}
os_dispatcher();
return;
}
// If the disk is busy, indicates failure in writing.
else if (status == DEVICE_IN_USE)
{
DISK_DATA *disk_data;
disk_data = (DISK_DATA *) calloc(1, sizeof ( DISK_DATA));
CurrentPCB->disk_id = disk_id;
CurrentPCB->operation = WRITE_ONE;
CurrentPCB->disk = disk_id;
CurrentPCB->sector = sector;
memcpy(disk_data, buffer, sizeof (DISK_DATA));
CurrentPCB->disk_data = disk_data;
result = add_to_suspend_queue(CurrentPCB);
if (result)
{
CurrentPCB->suspend = TRUE;
print_scheduling_info(ACTION_NAME_WRITE, CurrentPCB, NORMAL_INFO);
}
else
{
error_message("add_to_suspend_queue");
shut_down();
}
os_dispatcher();
return;
}
else
{
printf("some error not processed in os_disk_write!\n");
}
}
