この SystemVerilog コードに問題があります。コードは次のとおりです。
module mult ( multiplicand, multiplier, Product, clk, clear, Startm, endm );
input [31:0] multiplicand;
input [31:0] multiplier ;
input clk;
input clear;
input Startm;
output logic [63:0] Product;
output logic endm;
enum logic [1:0] { inicio, multiplicar, nao_multiplicar, fim } estados;
logic [1:0] state;
logic [31:0] mplier;
logic [31:0] mplier_aux;
logic [31:0] mcand ;
logic [31:0] mcand_aux;
logic [63:0] Prod ;
logic [63:0] Prod_aux;
logic [5:0] cont;
logic [5:0] cont_aux;
initial begin
mplier = multiplier;
mplier_aux = multiplier;
mcand = multiplicand;
mcand_aux = multiplicand;
Prod = 0;
Prod_aux = 0;
state = inicio;
cont = 0;
cont_aux = 0;
end
always_ff @( posedge clk )
begin
if( clear )
begin
state <= inicio;
end
else if ( Startm )
begin
case( state )
inicio :
begin
if( mplier[0] == 0 )
begin
state <= nao_multiplicar;
end
else if( mplier[0] == 1 )
begin
state <= multiplicar;
end
end
multiplicar :
begin
if( cont == 32 )
state <= fim;
else if( mplier[0] == 0 )
begin
state <= nao_multiplicar;
end
else if( mplier[0] == 1 )
begin
state <= multiplicar;
end
end
nao_multiplicar:
begin
if( cont == 32 )
state <= fim;
else if( mplier[0] == 0 )
begin
state <= nao_multiplicar;
end
else if( mplier[0] == 1 )
begin
state <= multiplicar;
end
end
fim:
begin
state <= inicio;
end
endcase
end
end
always_comb
begin
case(state)
inicio:
begin
mplier = multiplier;
mcand = multiplicand;
Prod = 0;
cont_aux = cont + 1;
cont = cont_aux;
end
multiplicar:
begin
mcand_aux = mcand << 1;
mcand = mcand_aux ;
mplier_aux = mplier >> 1;
mplier = mplier_aux ;
Prod_aux = Prod + mcand;
Prod = Prod_aux;
cont_aux = cont + 1;
cont = cont_aux;
end
nao_multiplicar:
begin
cont_aux = cont + 1;
cont = cont_aux;
end
fim:
begin
Product = Prod;
endm = 1;
end
endcase
end
endmodule
ブースのアルゴリズムを使用して、32 ビットの入力と 64 ビットの積を持つ乗算器を作成しようとしています。このエラーが発生します:
always_comb コンストラクトは、純粋な組み合わせロジックを推論しません
なぜこれが起こるのですか?