| 摘要 |
PURPOSE:To execute an operation of an undefined length operand, and also to execute a carry output from the most significant digit and a zero-detection of an significant digit by using a bit slice adder and subtracter. CONSTITUTION:The least significant digit of data to be operated A, B is allowed to be positioned in any digit, in an input of a decimal eight digit adder and subtracter 20. However, when the least significant digit of the data A, B is not positioned in the lowest digit of the input, it is required that the lower digit than the least significant digit is set to ''0''. Also, carry outputs CO0-CO7 from a decimal one digit adder and subtracter in the adder and subtracter 20 are supplied to a selector 40, and one of CO0-CO7 is selected and outputted as a carry output CO in accordance with the most significant digit position information EMSDP. An operation result Y is supplied to a digit zero detecting circuit 51, and a zero detection of each digit Y0-Y7 of the operation result Y is executed by an OR gate in the detecting circuit 51. |
