Data processing apparatus

摘要

A processor has two or more stacks. Each stack has a stack pointer. Each stack pointer is associated with a flag. The flag indicates whether the associated stack pointer has been initialised. The flags may be in a status register. The flags cannot be written by any instruction in the processorâ s instruction set. The processor may execute a soft reset if a stack pointer is used when the flag indicates it has not been initialised. The flag for a second stack may indicate that the associated stack pointer has not been initialised until the stack pointers for both the first and second stack pointers have been initialised.