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/*
* yosys -- Yosys Open SYnthesis Suite
*
* Copyright (C) 2012 Claire Xenia Wolf <claire@yosyshq.com>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* ---
*
* The internal logic cell simulation library.
*
* This Verilog library contains simple simulation models for the internal
* logic cells (_NOT_, _AND_, ...) that are generated by the default technology
* mapper (see "stdcells.v" in this directory) and expected by the "abc" pass.
*
*/
module _NOT_(A, Y);
input A;
output Y;
assign Y = ~A;
endmodule
module _AND_(A, B, Y);
input A, B;
output Y;
assign Y = A & B;
endmodule
module _OR_(A, B, Y);
input A, B;
output Y;
assign Y = A | B;
endmodule
module _XOR_(A, B, Y);
input A, B;
output Y;
assign Y = A ^ B;
endmodule
module _MUX_(A, B, S, Y);
input A, B, S;
output reg Y;
always @* begin
if (S)
Y = B;
else
Y = A;
end
endmodule
module _DFF_N_(D, Q, C);
input D, C;
output reg Q;
always @(negedge C) begin
Q <= D;
end
endmodule
module _DFF_P_(D, Q, C);
input D, C;
output reg Q;
always @(posedge C) begin
Q <= D;
end
endmodule
module _DFF_NN0_(D, Q, C, R);
input D, C, R;
output reg Q;
always @(negedge C or negedge R) begin
if (R == 0)
Q <= 0;
else
Q <= D;
end
endmodule
module _DFF_NN1_(D, Q, C, R);
input D, C, R;
output reg Q;
always @(negedge C or negedge R) begin
if (R == 0)
Q <= 1;
else
Q <= D;
end
endmodule
module _DFF_NP0_(D, Q, C, R);
input D, C, R;
output reg Q;
always @(negedge C or posedge R) begin
if (R == 1)
Q <= 0;
else
Q <= D;
end
endmodule
module _DFF_NP1_(D, Q, C, R);
input D, C, R;
output reg Q;
always @(negedge C or posedge R) begin
if (R == 1)
Q <= 1;
else
Q <= D;
end
endmodule
module _DFF_PN0_(D, Q, C, R);
input D, C, R;
output reg Q;
always @(posedge C or negedge R) begin
if (R == 0)
Q <= 0;
else
Q <= D;
end
endmodule
module _DFF_PN1_(D, Q, C, R);
input D, C, R;
output reg Q;
always @(posedge C or negedge R) begin
if (R == 0)
Q <= 1;
else
Q <= D;
end
endmodule
module _DFF_PP0_(D, Q, C, R);
input D, C, R;
output reg Q;
always @(posedge C or posedge R) begin
if (R == 1)
Q <= 0;
else
Q <= D;
end
endmodule
module _DFF_PP1_(D, Q, C, R);
input D, C, R;
output reg Q;
always @(posedge C or posedge R) begin
if (R == 1)
Q <= 1;
else
Q <= D;
end
endmodule
|
