Browse Prior Art Database

Direct Memory Access for Text Move

IP.com Disclosure Number: IPCOM000082403D
Original Publication Date: 1974-Dec-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 13K

Publishing Venue

IBM

Related People

Arthur, TG: AUTHOR [+3]

Abstract

A text processing system having a processor connected to a random-access memory through address, data-in, and data-out lines normally requires a great deal of time for moving text within the memory. This is because a processor, which is capable of processing only one character at a time, must perform arithmetic on address pointers and determine when conditions are met for terminating an operation.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 53% of the total text.

Page 1 of 2

Direct Memory Access for Text Move

A text processing system having a processor connected to a random-access memory through address, data-in, and data-out lines normally requires a great deal of time for moving text within the memory. This is because a processor, which is capable of processing only one character at a time, must perform arithmetic on address pointers and determine when conditions are met for terminating an operation.

For repositioning stored text, throughput is increased and time is saved by the addition of a command device, a source address control, and a destination address control. For purposes herein, each control is provided with capabilities of storing an address pointer and counting for indexing the pointer. Each control is connected to the address line between the processor and memory.

The command device is provided with the capability of storing an end-of- block address for comparison with the address pointer stored in the source address control, and has a register for storing data temporarily as it is being moved. The register is gate connected to the data-in and data-out lines between the processor and memory. The command device exercises control over the system through request line connections to the address controls as text moving is effected. The command device is also connected along a stop line to the processor, for causing the processor to stop for one or more cycles while text is being moved.

The address controls must be properly set up before a move command can be issued. The initial address of the data in memory is loaded into the source address control. The initial address of the destination is loaded into the destination address control, and the stop address is loaded into the command device. These addresses are loaded under processor program control.

Following set up, a command is issue...