If it is not possible to claim sufficient memory then the SWI will return an error, and the virtual memory will remain active. If the dynamic area is removed without virtual memory being first disabled then this SWI is implicitly called, but no check is made for locked pages. It is better to call this SWI explicitly to allow more elaborate checks to be performed. Lock pages of a dynamic area for which virtual memory has been enabled. End of range of addresses to lock.
Interrupt status is undefined.
Fast interrupts are enabled. Processor is in SVC mode. This enables the use of that area for interrupt routines, and other cases which could otherwise lead to reentrancy of either the virtual memory manager or the file system. This range must lie fully within the current size of a dynamic area for which virtual memory has been enabled. A count of how many times a page has been locked is maintained, and a page will only be unlocked when the count reaches zero.