| 摘要 |
PURPOSE:To allow a one-way shifter to shift at right and left sides without a special shifter circuit and to attain a quick digitmatching by the arithmetic of expotential data in a floating decimal point format by constituting the selection of a bit shift so that it can act in response to the generation of a complementary number. CONSTITUTION:Data on exponential parts of n-bits and a piece of data P and Q on mantesa parts of m-bits are added and subtracted. The addition and subtraction of floating decimal point data require digitmatching. However, normally the magnitudes of the exponential part data EP, and EQ are compared. In that case, a subtraction circuit 1 executes the arithmetic of EP-EQ, and a logic circuit 2 detects a case where the output of EQ-EP is requested. At that time a complementary number generator circuit 3 generates one complementary number of the subtraction result, while a decoder 4 decodes the result through a multiplexer 5, and generates a control signal with a shift amount corresponding to the complementary number. A shift circuit 6 shifts a generated control signal in a direction where one bit increases, and a multiplexer 7 leads said amount to a shifter circuit 7, whereby the shift amount is controlled. |
