定点分数

Question

我有点问题。我想做一个用固定点划分两个数字的程序。我的输出看起来没问题，但是当我在a上测试程序时 本地测试网站我得到了一些奇怪的结果。有人可以帮助我吗？谢谢。

module divider(
        input[7:0] a,b,
        output reg [15:0] q,
        output reg [7:0] r,frac
          );

        reg[7:0] c2, r2;
        integer c;
    always @(*)
        begin

        c = 8'b00000000;
        r = a;
          frac = 8'b00000000;

        repeat (30)
            begin
               if (r >= b )
                  begin
                    c = c + 1;
                    r = r - b;
                  end
             end

          q[15:8] = c;



        repeat (8)
        begin
          if(r != 0)
                begin
                r = r*10;
                c2 = 8'b00000000;

                repeat(30)
                    begin

                    if (r>=b)
                        begin
                        c2 = c2 + 1;
                        r = r-b;
                        end
                    end
                frac = frac*10 + c2;
                end
            end

             q[7:0] = frac;








end

endmodule

输出本地网站：

error: a =   1, b =   2, q = 0.019531, expected q = 0.500000
error: a =   1, b =   4, q = 0.097656, expected q = 0.250000
error: a =   1, b =   5, q = 0.007813, expected q = 0.199219
error: a =   1, b =   7, q = 0.570313, expected q = 0.140625
error: a =   1, b =   8, q = 0.488281, expected q = 0.125000
error: a =   1, b =   9, q = 0.777344, expected q = 0.109375
error: a =   1, b =  10, q = 0.003906, expected q = 0.097656
error: a =   1, b =  11, q = 0.363281, expected q = 0.089844
error: a =   1, b =  14, q = 0.785156, expected q = 0.070313
error: a =   1, b =  15, q = 0.664063, expected q = 0.066406
error: a =   1, b =  16, q = 0.441406, expected q = 0.062500
error: a =   1, b =  17, q = 0.937500, expected q = 0.058594
error: a =   1, b =  18, q = 0.386719, expected q = 0.054688
error: a =   1, b =  19, q = 0.207031, expected q = 0.050781
error: a =   1, b =  20, q = 0.019531, expected q = 0.046875
error: a =   1, b =  21, q = 0.187500, expected q = 0.046875
error: a =   1, b =  22, q = 0.679688, expected q = 0.042969
error: a =   1, b =  23, q = 0.695313, expected q = 0.042969
error: a =   1, b =  25, q = 0.015625, expected q = 0.039063
error: a =   1, b =  27, q = 0.589844, expected q = 0.035156
error: a =   1, b =  28, q = 0.890625, expected q = 0.035156
error: a =   1, b =  29, q = 0.824219, expected q = 0.031250
error: a =   1, b =  30, q = 0.832031, expected q = 0.031250
error: a =   1, b =  31, q = 0.804688, expected q = 0.031250
error: a =   1, b =  32, q = 0.207031, expected q = 0.031250
error: a =   1, b =  33, q = 0.121094, expected q = 0.027344
error: a =   1, b =  34, q = 0.437500, expected q = 0.027344
error: a =   1, b =  35, q = 0.570313, expected q = 0.027344
error: a =   1, b =  36, q = 0.914063, expected q = 0.027344
error: a =   1, b =  37, q = 0.000000, expected q = 0.023438
error: a =   1, b =  38, q = 0.339844, expected q = 0.023438
error: a =   1, b =  40, q = 0.097656, expected q = 0.023438

Answer 1

您不一定需要基数10来进行FPGA上的划分。 Radix2划分（例如shift and subtract）将更快更容易实现。我找到了this radix2 division的例子。