Stack oriented data processing device
AssigneeKoninklijke Philips Electronics N.V.
InventorsMarnix C. Vlot, Paul E. R. Lippens
Life of this patent
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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:
- maintaining means for maintaining a first stack and a second stack;
- and
- an instruction execution unit having an instruction set containing first instructions and second instructions causing a push and/or pop of the first stack and the second stack, respectively,
- wherein said maintaining means pushes and/or pops information in basic units of a first length and a second length on the first stack and the second stack, respectively, the first length and the second length being unequal and not an integer multiple of one another.
A data processing device, comprising:
- maintaining means for maintaining a first stack and a second stack;
- and
- an instruction execution unit having an instruction set containing first instructions and second instructions causing a push and/or pop of the first stack and the second stack, respectively,
- wherein said maintaining means pushes and/or pops information in basic units of a first length and a second length on the first stack and the second stack, respectively, the first length and the second length being unequal, and in that the instruction set uses a first addressing mode and a second addressing mode for designating storage locations in terms of an offset relative to a top of the first stack and the second stack, respectively, expressability of the offset being restricted to numbers of basic units for the first stack and the second stack.
Dependencies are inferred from the claim text.