| 摘要 |
A high speed barrel shifter in which fill input data is especially added. The high speed barrel shifter comprises: a first multiplexer having a first and a second input terminals for receiving double word and input data, thereby producing fill data at a first multiplexer output terminal responsive to first and second fill data control signals (C1, C2); a second multiplexer coupled to said first multiplexer for receiving the fill data output from said first multiplexer and the input data and producing first shifted data by shifting the input data by a selectable number of either 0 or 4 bits and by replacing selectable input data bits with selectable fill data bits responsive to a first shift control signal (M0); a third multiplexer coupled to said second multiplexer for receiving the first shifted data output from said second multiplexer and producing second shifted data by shifting the first shifted data by a selectable number of either 0, 1, 2, or 3 bits responsive to second and third shift control signals (M1, M2); and a fourth multiplexer coupled to said first and third multiplexer for receiving the fill data output from said first multiplexer and the second shifted data output from said third multiplexer and selecting output data responsive to a first and second output select control signals (F, H). |
