Subversion Repositories sbd_sqrt_fp

/****************************************************************************

sbd_shifter_left3_right2

- shift register - shifts left - towards MSB - 3 bits or shifts right -

   towards LSB - 2 bits

Copyright (C) 2005 Samuel Brown

sam.brown@sbdesign.org

This library is free software; you can redistribute it and/or

modify it under the terms of the GNU Lesser General Public

License as published by the Free Software Foundation; either

version 2.1 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public

License along with this library; if not, write to the Free Software

Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

****************************************************************************/

module sbd_shifter_left3_right2 (SINLSB,SINMSB,PIN,LOAD,LR,RST,SHIFT,CLK,POUT);

parameter bitlength = 48;

input [2:0] SINLSB;

input [1:0] SINMSB;

input [bitlength-1:0] PIN;

input LOAD;

input LR;

input RST;

input SHIFT;

input CLK;

output wire [bitlength-1:0] POUT;

reg [bitlength-1:0] writeData, readData;

wire [1:0] sel = { LOAD, LR };

assign POUT = readData;

always @ ( posedge CLK)

begin:shiftreg

   if(RST) readData <= 0;

   else if(SHIFT | LOAD) readData <= writeData;

end

always @ (sel, readData, SINLSB, SINMSB, PIN)

begin:loadmux

   casez(sel)

      2'b00: writeData = { readData[bitlength-4:0], SINLSB };

      2'b01: writeData = { SINMSB, readData[bitlength-1:2] };

      2'b1z: writeData = PIN;

   endcase

end

endmodule