为可合成VHDL使用非常量实值表达式时出错 当f9=> 如果melcol

如注释中所述，对于合成应用程序，不应使用

real

类型，而应根据可合成的固定或浮点类型定义逻辑。您可能会发现，在更改逻辑以使用这些新类型的过程中，您需要重新思考如何实现您试图实现的目标

如其他人在评论中所述，查看以下资源：

• 和点类型的用户指南
• 您正在使用的合成工具的手册/用户指南。例如

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我认为您需要阅读这些。。。和

 when f9 =>
       if melcol < 128 and framcounter < 2560 then
           temp <= std_logic_vector(signed(framout)*to_signed(melf(melrow,melcol),8));
           firstmelout <= firstmelout + (to_integer(unsigned(temp)))/1000;
           melcol <= melcol+1;
           framcounter <= framcounter+1;
           fstate <= f9;
       elsif melcol = 128 and melrow < 13 and framcounter < 2560 then
           -----MEMORY NEEDED
           framcounter <= framcounter -128;
           melrow <= melrow+1;      --melrow filter number
           melcol <= 0;
           secondmelout <= firstmelout;
           fstate <= f10;
       elsif melcol = 128 and melrow = 13 and framcounter < 2560 then
           ---------MEMORY NEEDED
           framcounter <= framcounter +128;
           melrow <= 0;
           melcol <= 0;
           secondmelout <= firstmelout;
           fstate <= f10;
       elsif framcounter = 2560 then
           flagmel <= '1';
           fstate <= f12;
       else fstate <= f12;
       end if;

   when f10 =>
       varmel <= real(secondmelout);
       --varmel := LOG10(firstmelout);
       --varlogresult := 100*varlogresult;
       wea3(0) <= '1';
       --logresult <= intlogresult;
       fstate <= f11;