# IC_Unlockdown

## C Specification

      #include <nitro/os.h>

      void IC_Unlockdown( u32 num );

## Arguments

num | Designates the number of lockdown blocks to deallocate.

## Return Values

None.

## Description

Instruction cache can be locked with `IC_LockdownRange`, which prevents the cache from being deleted. `IC_Unlockdown` releases the instruction cache to be deleted when the cache is replaced. This function releases, in order, a `num` number of lockdown blocks from the region that was last locked with the `IC_LockdownRange` function. There are a maximum of three configurable lockdown blocks, so the maximum number of lockdown blocks designated with `num` is also three.

## Internal Operation

Operates registers 7 and 9 of the system control coprocessor.

## See Also

`IC_LockdownRange,IC_UnlockdownAll`

## Revision History

01/21/2005 Initial Version