Function emit_simd_fmul_f16x4_verilog 

pub fn emit_simd_fmul_f16x4_verilog() -> String

Emit the packed F16×4 multiply tile: four fp16_mul lanes. Module simd_fmul_f16x4. Compile alongside FP16_MUL_V; proven ≡ eval_lanewise_fmul_f16x4 under iverilog.