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Micro-Program System Stack Pointer Sub-Unit

IP.com Disclosure Number: IPCOM000063355D
Original Publication Date: 1985-Mar-01
Included in the Prior Art Database: 2005-Feb-18

Publishing Venue

IBM

Related People

Authors:
Kriz, TA [+details]

Abstract

This sub-unit provides 16 separate stack pointers to support fast indirect access of vector operands in an attached data store. Ordinary stack pointer and index register structures do not allow arbitrary incrementation update to support address generation for a variety of stepped patterns. A diagram of the sub-unit is shown in the figure indicating the 16 separate pointers. Each of these are initialized to point to some locus of an operand string by loading a selected pointer register location of the Stack Pointer RAM (random-access memory) shown in the diagram. After initialization, the stack pointer is used for indirect data address reference by asserting an instruction op-code which commands use of the Stack Pointer to form an operand address (in place of a direct pointer from the micro-code instruction literal field).