(SWI &C100a)

On entry: 
R0 =  Previously allocated vector handle
On exit: All registers preserved
Interrupts: Interrupt status is unaltered
Fast interrupts are enabled
Processor Mode:  Processor is in SVC mode
Re-entrancy: SWI is not reentrant
Use: This call uninstalls a handler previously allocated by CallWin32_VectorAllocate. Once completed, the handler is guaranteed to not be called again.
Related SWIs: CallWin32_VectorAllocate (SWI &C1009)