CARRY4 example for Series 7 FPGA¶

CARRY4 defined directly¶

module CARRY4(output [3:0] CO, O, input CI, CYINIT, input [3:0] DI, S);
  assign O = S ^ {CO[2:0], CI | CYINIT};
  assign CO[0] = S[0] ? CI | CYINIT : DI[0];
  assign CO[1] = S[1] ? CO[0] : DI[1];
  assign CO[2] = S[2] ? CO[1] : DI[2];
  assign CO[3] = S[3] ? CO[2] : DI[3];
endmodule

.. hdl-diagram:: ../code/verilog/carry4-whole.v
   :type: netlistsvg
   :module: CARRY4

/home/docs/checkouts/readthedocs.org/user_builds/sphinxcontrib-verilog-diagrams/checkouts/latest/docs/code/verilog/carry4-whole.v

CARRY4 defined by components¶

`include "muxcy.v"
`include "xorcy.v"

module CARRY4(output [3:0] CO, O, input CI, CYINIT, input [3:0] DI, S);
   wire CIN = CI | CYINIT;

   MUXCY muxcy0 (.O(CO[0]), .CI(CIN),   .DI(DI[0]), .S(S[0]));
   MUXCY muxcy1 (.O(CO[1]), .CI(CO[0]), .DI(DI[1]), .S(S[1]));
   MUXCY muxcy2 (.O(CO[2]), .CI(CO[1]), .DI(DI[2]), .S(S[2]));
   MUXCY muxcy3 (.O(CO[3]), .CI(CO[2]), .DI(DI[3]), .S(S[3]));

   XORCY xorcy0 (.O(O[0]), .CI(CIN),   .LI(S[0]));
   XORCY xorcy1 (.O(O[1]), .CI(CO[0]), .LI(S[1]));
   XORCY xorcy2 (.O(O[2]), .CI(CO[1]), .LI(S[2]));
   XORCY xorcy3 (.O(O[3]), .CI(CO[2]), .LI(S[3]));
endmodule

module MUXCY(output O, input CI, DI, S);
  assign O = S ? CI : DI;
endmodule

module XORCY(output O, input CI, LI);
  assign O = CI ^ LI;
endmodule

MUXCY¶

.. hdl-diagram:: ../code/verilog/muxcy.v
   :type: netlistsvg
   :caption: muxcy.v
   :module: MUXCY

muxcy.v¶

XORCY¶

.. hdl-diagram:: ../code/verilog/xorcy.v
   :type: netlistsvg
   :caption: xorcy.v
   :module: XORCY

xorcy.v¶

CARRY4 without flatten¶

.. hdl-diagram:: ../code/verilog/carry4-bits.v
   :type: netlistsvg
   :module: CARRY4
   :caption: carry4-bits.v without flatten

/home/docs/checkouts/readthedocs.org/user_builds/sphinxcontrib-verilog-diagrams/checkouts/latest/docs/code/verilog/carry4-bits.v

carry4-bits.v without flatten¶

CARRY4 with flatten¶

.. hdl-diagram:: ../code/verilog/carry4-bits.v
   :type: netlistsvg
   :module: CARRY4
   :flatten:
   :caption: carry4-bits.v with flatten

carry4-bits.v with flatten¶