| 摘要 |
<p>1508735 Verifying INTERNATIONAL BUSINESS MACHINES CORP 30 June 1976 [16 July 1975] 27310/76 Addition to 1499734 Headings G4A and G4R To verify input words as valid, each input character N is converted to a number L N (in memory 10, Fig. 1), squared (in multiplier 12) and a magnitude #L<SP>2</SP> N formed (in register 17). Simultaneously (1) each character L N is multiplied by a unique number R N indicating its position in the word and the sum #R N .L N formed (in register 24) and (2) the sum #R<SP>2</SP> N is formed (in register 34). |Y| = ##L<SP>2</SP> N and |R| = ##R<SP>2</SP> N are derived by square root circuits 27, 36 and the value |Y| |R| / #L N R N fed to an arc secant calculator to derive an angle. Angles representing data words in a dictionary are stored in memory 38 at an address dependent on their magnitude #L<SP>2</SP> N and consequently the computed magnitude is used to access the memory to read out to buffer store 45 any angle stored at that address, comparator 41 setting a flip-flop 42 if a match is found between the computed and stored angles. As described a mod 256 convention is used to store the angles and so reduce the storage space required, an index coder giving the start address for each set of 256 units. The number of angles following a stored angle is given by the last three bits of a four bit header, the first bit indicating whether or not the angle it follows relates to a value of one unit larger than the preceding value.</p> |
