Method and apparatus for unstacking registers in a data processi

Details Method and apparatus for unstacking registers in a data processi Method and apparatus for unstacking registers in a data processi

1992-10-19

1997-06-17

Lall, Parshotam S.

395378, 395591, G06F 930, G06F 946

Patent

active

056405480

ABSTRACT:
A method and apparatus for unstacking registers in a data processing system (100). In one form, the present invention is a more time efficient solution to the problem of unstacking and stacking registers (154-158) during interrupt processing in a data processing system (100). By taking advantage of the fact that pulling a register value off of the stack does not change any of the values stored in the memory which is being used as the stack, the present invention reduces the unstacking and stacking each time that two interrupts are processed back to back with no non-interrupt processing in between. The present invention eliminates the unstacking of the program counter register (158) and the restacking of registers (154-158) by changing the value of the stack pointer register (161) without any corresponding stacking or unstacking operation.

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