OpenFPGA/openfpga_flow/benchmarks/iwls2005/des/area_opt/rtl/sbox4.v

114 lines
4.0 KiB
Verilog

/////////////////////////////////////////////////////////////////////
//// ////
//// SBOX ////
//// The SBOX is essentially a 64x4 ROM ////
//// ////
//// Author: Rudolf Usselmann ////
//// rudi@asics.ws ////
//// ////
/////////////////////////////////////////////////////////////////////
//// ////
//// Copyright (C) 2001 Rudolf Usselmann ////
//// rudi@asics.ws ////
//// ////
//// This source file may be used and distributed without ////
//// restriction provided that this copyright statement is not ////
//// removed from the file and that any derivative work contains ////
//// the original copyright notice and the associated disclaimer.////
//// ////
//// THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY ////
//// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED ////
//// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS ////
//// FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHOR ////
//// OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, ////
//// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES ////
//// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE ////
//// GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR ////
//// BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF ////
//// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ////
//// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT ////
//// OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE ////
//// POSSIBILITY OF SUCH DAMAGE. ////
//// ////
/////////////////////////////////////////////////////////////////////
module sbox4(addr, dout);
input [1:6] addr;
output [1:4] dout;
reg [1:4] dout;
always @(addr) begin
case ({addr[1], addr[6], addr[2:5]}) //synopsys full_case parallel_case
0: dout = 7;
1: dout = 13;
2: dout = 14;
3: dout = 3;
4: dout = 0;
5: dout = 6;
6: dout = 9;
7: dout = 10;
8: dout = 1;
9: dout = 2;
10: dout = 8;
11: dout = 5;
12: dout = 11;
13: dout = 12;
14: dout = 4;
15: dout = 15;
16: dout = 13;
17: dout = 8;
18: dout = 11;
19: dout = 5;
20: dout = 6;
21: dout = 15;
22: dout = 0;
23: dout = 3;
24: dout = 4;
25: dout = 7;
26: dout = 2;
27: dout = 12;
28: dout = 1;
29: dout = 10;
30: dout = 14;
31: dout = 9;
32: dout = 10;
33: dout = 6;
34: dout = 9;
35: dout = 0;
36: dout = 12;
37: dout = 11;
38: dout = 7;
39: dout = 13;
40: dout = 15;
41: dout = 1;
42: dout = 3;
43: dout = 14;
44: dout = 5;
45: dout = 2;
46: dout = 8;
47: dout = 4;
48: dout = 3;
49: dout = 15;
50: dout = 0;
51: dout = 6;
52: dout = 10;
53: dout = 1;
54: dout = 13;
55: dout = 8;
56: dout = 9;
57: dout = 4;
58: dout = 5;
59: dout = 11;
60: dout = 12;
61: dout = 7;
62: dout = 2;
63: dout = 14;
endcase
end
endmodule