"stack oriented data processing device "
AssigneePhilips Corporation
InventorsMARNIX C. VLOT, PAUL E.R. LIPPENS
Life of this patent
Estimating the term…
Abstract
The data processing device maintains two stacks. The length of the basic unit of information is different for each stack. Pops and pushes cause a change in the stack pointer which differs dependent on which stack is used. Instructions refer to different locations on the stack as registers defined by an offset of a number of basic units relative to the top of stack. In an embodiment a reference to registers is normally interpreted as a reference to one of a set of registers (including the top of stack register) without push or pop, but a reference to one register is interpreted as a reference to top of stack including a push or pop.
Claims8
A data processing device comprising
- means for maintaining a first and second stack,
- an instruction execution unit having an instruction set containing first and second instructions causing a push and/or pop of the first and second stack respectively, characterized in that the means for maintaining push and/or pop information in basic units of a first and second length on the first and second stack respectively, the first and second length being unequal, and not an integer multiple of one another.
A data processing device comprising
- means for maintaining a first and second stack,
- an instruction execution unit having an instruction set containing first and second instructions causing a push and/or pop of the first and second stack respectively, characterized in that the means for maintaining push and/or pop information in basic units of a first and second length on the first and second stack respectively, the first and second length being unequal, and in that the instruction set uses a first and second addressing mode for designating storage locations in terms of an offset relative to a top of the first and second stack respectively, expressability of the offset being restricted to numbers of basic units for the appropriate stack.
Dependencies are inferred from the claim text.