问题
I want to parse the following sequential gate level net list. And I expect that the output will give me the gate ordering ( port order) so I can do other computation on the code.
I tried to do that using yosys command read_verilog s27.v
. I was able to debug the code, yet I could not get the cell library or any thing that will get me the gate ordering.
P.S: I tried that using abc compiler and I only got the primary inputs and outputs order not the gate, and I asked before if yosys can do that and I got positive feedbacks.
module s27 ( GND, VDD, CK, R, G0, G1, G17, G2, G3 );
input GND, VDD, CK, R, G0, G1, G2, G3;
output G17;
wire G5, G10, G6, G7, G13, n1, n2, n3, n4, n5, n6, n7, n8, n9, n11,
n12,n13, n14;
DFFSR \DFF_2/Q_reg ( .D(G13), .CLK(CK), .R(R), .Q(G7) );
DFFSR \DFF_0/Q_reg ( .D(G10), .CLK(CK), .R(R), .Q(G5) );
DFFSR \DFF_1/Q_reg ( .D(n1), .CLK(CK), .R(R), .Q(G6) );
INVX1 U1 ( .A(G17), .Y(n1) );
INVX1 U2 ( .A(G2), .Y(n2) );
INVX1 U3 ( .A(G3), .Y(n3) );
INVX1 U4 ( .A(G6), .Y(n4) );
AND2X1 U5 ( .A(n5), .B(n2), .Y(G13) );
AND2X1 U6 ( .A(G0), .B(G17), .Y(G10) );
OR2X1 U7 ( .A(n6), .B(n7), .Y(G17) );
OR2X1 U8 ( .A(n14), .B(n8), .Y(n7) );
AND2X1 U9 ( .A(n5), .B(n9), .Y(n8) );
OR2X1 U10 ( .A(G1), .B(n12), .Y(n5) );
AND2X1 U11 ( .A(n3), .B(n9), .Y(n6) );
OR2X1 U12 ( .A(G0), .B(n4), .Y(n9) );
INVX1 U13 ( .A(G7), .Y(n11) );
INVX1 U14 ( .A(n11), .Y(n12) );
INVX1 U15 ( .A(G5), .Y(n13) );
INVX1 U16 ( .A(n13), .Y(n14) );
endmodule
回答1:
The newly added torder command prints the cells in the design in topological order, if such an order exists. For example:
read_verilog test.v
hierarchy -generate * o:Y o:Q i:*
torder -stop DFFSR Q
This script applied to the code you posted produces the following output:
module s27
cell U4
cell U12
cell U3
cell U11
cell U15
cell U16
cell U13
cell U14
cell U10
cell U9
cell U8
cell U7
cell U6
cell DFF_0/Q_reg
cell U1
cell DFF_1/Q_reg
cell U2
cell U5
cell DFF_2/Q_reg
Without the -stop
option the command would also create dependencies for DFF output ports, which would result in loops. In such a case the command will print the loops and create a topological ordering for the remaining graph:
module s27
loop DFF_2/Q_reg U10 U13 U14 U5
loop DFF_0/Q_reg U15 U16 U6 U7 U8
loop DFF_1/Q_reg U1 U11 U12 U4 U7
cell U1
cell DFF_1/Q_reg
cell U4
cell U12
cell U3
cell U11
cell U15
cell U16
cell U2
cell U5
cell DFF_2/Q_reg
cell U13
cell U14
cell U10
cell U9
cell U8
cell U7
cell U6
cell DFF_0/Q_reg
I hope this helps.
来源:https://stackoverflow.com/questions/33756400/gate-level-parsing-using-yosys