Verilog conditional compilation implementation - FPGA design

Verilog conditional compilation implementation - FPGA design

As FPGAs are more and more widely used in various industries, FPGA design engineers need to flexibly carry out different customized designs according to different scenarios. The conditional compilation (Conditional Compilation) mechanism of Verilog language can realize the selective compilation of code according to different conditions, which provides great convenience for FPGA customized design.

The following briefly introduces how to use the conditional compilation mechanism of Verilog language in FPGA design.

The syntax format of Verilog conditional compilation is:

`ifdef <macro_name>
code block
`elsif <macro_name2>
code block2
`else
code block3
`endif

Among them, ifdef 是条件编译指令，它会检查编译时预定义变量 whether macro_name has been defined. If this macro has been defined, compile the code block code block.

And elsif 是 elsif 缩写，与 if 语句的使用方法基本相同，只要缩写了一下。它表示 the macro_name macro is not defined, then check another macro macro_name2 是否被定义。若macro_name2 is defined, then compile the code block2 code block.

Finally, if all macros are undefined, the code block3 code block is compiled.

Below, we use an example to demonstrate the application of the conditional compilation mechanism:

module test #(parameter WIDTH = 8) (
    input logic [WIDTH-1:0] a,
    input logic [WIDTH-1:0] b,
    output logic [WIDTH-1:0] c
    );
    &