IBM TIE6309-0453 1401coreStrech free download

File name TIE6309-0453_1401coreStrech.pdf

ITEM NUMOER 6309-0453 (T.I.~.J 14 pages ;OATE August 5, 1963 AUTHOR Frans P. Oudheusden 1rITLE 1401 CORE: STRETCHING FOR TABLE LOOK-UP SOURCE IBM CORPORA TION 1111 Connecticut Avenue Washington 6, D. C. Thla paper 10 In the author'a origlnal form. The obJectlve In providing thlu copy Is to keep you Informed In your fIeld of Interest. Please do not dIstribute thIs paper to persono outsIde the IBM Company. ---- -------_... _-----_-... .IBM ...CONFIDENTIAL 6309 0453 DISTRIBUT:ED BY THE PROGnAM INFORMA TION DEPAR TMENT (TIE) I.BM CORP. 11 Z EAST POST ROAD VVmTE PLAINS, NY TABLE OF CONTENTS Page Acknowledgment of Assistance Letter 3 Abstract 4 Introduction 5 The Single Character Conversion Technique 6-8 The Randomizing and Chaining Approach 9-10 The Multipass Table Look-Up 11-12 Figure 1 - Modulus 16 Arithmetic 13 Figure 2 - Core Storage Layout 14 Figure 3 - Binary to Octal Conversion Routine Flowchart 15 ABSTRACT 1. 1401 Core Str1etching for Table Look-Up 2. Frans P. Oudheusden Scientific & Special Operations Program Department 0:36 Data Processing Division Washington Federal Region 1111 Connecticut Avenue, N. W. Washington 6" D. C. 333-6700 Ext. 455 3. Unique table look-up techniques are described emphasizing compactness, speed and flexibility. The discussions cover a single character conversion technique, a randomizing and chaining approach and a multipass procedure for tables exceeding core storage capacity. The single character conversion uses the four bit arithmetic of the 1401 core addressing scheme. This is illustrated by an example of binary to octal trans- formation. The randomizing and chaining technique continues this example by converting the octal to 7094 language mnemonics. The multipass approach, illustrated by an editing problem, utilizes the tape load mode to identify errors with wordmarks. Page 4 INTRODUCTION This paper is intended to acquaint the reader with some unusual approaches to three widely different table look-up requirements. It is improbable that the reader will be confronted with similar problems on identical hardware, however, he may be able to use a variation of the techniques