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Packet Length Calculator

IP.com Disclosure Number: IPCOM000064516D
Original Publication Date: 1985-Jul-01
Included in the Prior Art Database: 2005-Feb-19

Publishing Venue

IBM

Related People

Authors:
Awsienko, O Nahata, P [+details]

Abstract

A technique is described whereby a simple algorithm is used, with an inverter and a ripple carry incrementor, to determine the initial packet size of data to be transferred. The technique is particularly useful in computer architecture where the transfer of data from a master direct memory access (DMA) controller is dependent upon the number of bytes which make up the line length. The data packet size never exceeds the line length to which the data is being transferred. In many designs of DMA controllers, the device seeking access to the memory of another device requires a starting address and the total number of bytes of data to be transferred to the DMA controller. It is advantageous to employ the packet concept for DMA controllers where the data packet size is based on the line length of the receiving device.