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Single Cycle Execution of Immediate Instructions

IP.com Disclosure Number: IPCOM000056476D
Original Publication Date: 1980-Dec-01
Included in the Prior Art Database: 2005-Feb-14

Publishing Venue

IBM

Related People

Authors:
Chang, DC Gemmel, MN Rymarczyk, JW Spraul, WP [+details]

Abstract

This article describes the implementation of IBM System/370 immediate instructions using a new and separate logical unit to reduce execution time. Previously the execution of the immediate instructions NI, OI, and XI required 2 cycles. The first cycle was to perform the logical function in a normal data path logical unit, and the second cycle was used to gate the result through a shifter to a cache input register.