# DC_StoreRange

## C Specification

      #include <nitro/os.h>

      void DC_StoreRange( const void* startAddr, u32 nBytes );

      void DC_CleanRange( const void* startAddr, u32 nBytes );

## Arguments

startAddr | Lowest address in the range to be cleaned
nBytes | Number of bytes of the range to be cleaned

## Return Values

None.

## Description

This function stores the specified region of data cache to memory.

Specifically, it performs a cache writeback in a dirty state (state when a write to data cache corresponding to a specified memory region is not reflected in main memory) and places it in an clean state (state where all stored values in cache match memory contents).

Call this function when completing data transmission data blocks that use the main memory of other devices, such as when performing DMA transfers or creating graphics commands.

`startAddr` is rounded down to the closest 32-byte boundary. `startAddr` + `nBytes` is rounded up to the closest 32-byte boundary.

`DC_CleanRange()` is another name for `DC_StoreRange()` and operates exactly the same way.
`DC_Clean*/DC_CleanAndInvalidate*` were prepared for porting from the prototype SDK version. In most cases, use `DC_Store*/DC_Flush*`.

The official documentation for the ARM processor sometimes describes Flush as the operation that invalidates the data cache, Clean as the operation that writes back the data cache and puts it into a clean state, and Clean and Flush as the operation that writes back and then invalidates. However, this SDK follows the conventions of the Nintendo GameCube and Nintendo64 by using Invalidate for invalidation, Store for writeback, and Flush for writeback and invalidate operations.

## Internal Operation

Operates register 7 of the system control coprocessor. This function divides the specified range into cache-line units and repeats its operation. Thus the amount of time it takes is proportional to the size of the range. If the range is large and you can properly manage cache for the whole application, calling `DC_StoreAll` will require less processing time.

## See Also

`DC_InvalidateAll DC_StoreAll DC_FlushAll DC_InvalidateRange DC_FlushRange`

## Revision History

11/14/2005 Changed the type of `startAddr` to `const void*`.
04/19/2005 Added a description of the reason why processing time is proportional to the size of the memory region.
12/22/2003 Initial release.

CONFIDENTIAL