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`timescale 1ns / 1ps

// ============================================================================

//        __

//   \\__/ o\    (C) 2006-2016  Robert Finch, Waterloo

//    \  __ /    All rights reserved.

//     \/_//     robfinch<remove>@finitron.ca

//       ||

//

//      fpLOOUnit.v

//              - single cycle latency floating point unit

//              - parameterized width

//              - IEEE 754 representation

//

//

// This source file 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 3 of the License, or     

// (at your option) any later version.                                      

//                                                                          

// This source file 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 General Public License for more details.                             

//                                                                          

// You should have received a copy of the GNU General Public License        

// along with this program.  If not, see <http://www.gnu.org/licenses/>.    

//                                                                          

//      i2f - convert integer to floating point

//  f2i - convert floating point to integer

//

// ============================================================================

`define FLOAT   6'h36

`define FTOI    6'h02

`define ITOF    6'h03

module fpLOOUnit

#(parameter WID=32)

(

        input clk,

        input ce,

        input [31:0] ir,

        input [WID-1:0] a,

        output reg [WID-1:0] o,

        output done

);

localparam MSB = WID-1;

localparam EMSB = WID==128 ? 14 :

                  WID==96 ? 14 :

                  WID==80 ? 14 :

                  WID==64 ? 10 :

                                  WID==52 ? 10 :

                                  WID==48 ? 10 :

                                  WID==44 ? 10 :

                                  WID==42 ? 10 :

                                  WID==40 ?  9 :

                                  WID==32 ?  7 :

                                  WID==24 ?  6 : 4;

localparam FMSB = WID==128 ? 111 :

                  WID==96 ? 79 :

                  WID==80 ? 63 :

                  WID==64 ? 51 :

                                  WID==52 ? 39 :

                                  WID==48 ? 35 :

                                  WID==44 ? 31 :

                                  WID==42 ? 29 :

                                  WID==40 ? 28 :

                                  WID==32 ? 22 :

                                  WID==24 ? 15 : 9;

wire [WID-1:0] i2f_o;

wire [WID-1:0] f2i_o;

wire [5:0] op = ir[5:0];

wire [5:0] fn = ir[17:12];

wire [2:0] rm = ir[26:24];

wire [1:0] prec = ir[28:27];

delay1 u1 (.clk(clk), .ce(ce), .i(op==`FLOAT && (fn==`ITOF||fn==`FTOI)), .o(done) );

i2f #(WID)  ui2fs (.clk(clk), .ce(ce), .rm(rm), .i(a), .o(i2f_o) );

f2i #(WID)  uf2is (.clk(clk), .ce(ce), .i(a), .o(f2i_o) );

always @*

        case (op)

        `FLOAT:

       case(fn)

       `ITOF:   o <= i2f_o;

       `FTOI:   o <= f2i_o;

       default: o <= 0;

       endcase

    default:   o <= 0;

    endcase

endmodule