EQUIPMENT AND METHOD FOR ADDITION AND SUBTRATION OF THERMOMETER CODING DATA

PURPOSE: To easily perform an arithmetic operation on many figure displays of thermometer coded data. CONSTITUTION: When checking blocks 12 and 14 detect a 1st borrow state in which an MSB(most significant byte) of a word B is larger than that of a word A and also an LSB(least significant byte) of the word A is larger than that of the word B, a word B borrow block 16 shifts the MSB of the word B to the right, and when checking blocks 18 and 20 detect a 2nd borrow state in which the MSB of the word A is larger than that of the word B and the LSB of the word B is larger than that of the word A, the word B borrow block 22 shifts the MSB of the word A to the right. Then an MSB subtraction block 24 performs an exclusive OR operation of both arithmetic results and these results are shifted by an MSB reproduction block 26 to the right stored in a proper thermometer code format. An LSB subtraction block 32 performs an exclusive OR operation of LSB borrow results which are turned into the proper types by translation blocks 28 and 30, and an LSB reproduction block 34 shifts the arithmetic results to the right and rotates them to the left to store them in a proper format. If no borrow exists, no shift is carried out and an exclusive OR operation is performed.