RTL Design: Verilog vs SystemVerilog

Same family, different goals

Verilog (IEEE 1364) is for design. SystemVerilog (IEEE 1800) extends it with verification features – classes, constraints, assertions.

Use Verilog when

• Writing pure synthesizable RTL
• Targeting older toolchains
• Keeping a clean design/test split

Use SystemVerilog when

• Writing testbenches (UVM requires it)
• You want logic, always_ff, always_comb for clean intent
• You need interfaces and modports to tame SoC complexity

always_ff @(posedge clk or negedge rst_n) begin
  if (!rst_n) q <= '0;
  else        q <= d;
end