請教 Synplify "reduced to a combinational gate by constant propagation"

kuhwakimo

請教 Synplify Pro9.6.1 Warning Message
9 D' {0 x: i- j/ ySequential instance sLateCol_p has been Sequential instance sLateCol_p has been reduced to a combinational gate by constant propagation
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請教個問題，下面是Synplify 9.6.1 出現的Warning message ,
) G+ ~$ [8 t! t# g) L請問這是什麼意思　??
6 w, \8 d; k- q( P0 s4 D我由字面上的理解得到的猜測是，將一個本應該是FIFO Sequential circuit ,合成為 Multiplier Combinational circuit
" ?" Z+ T7 q% e! `" p* @4 ]為什麼　ld_tdr_cur_f　會被合成為Combinational, 但是 dly_tdr_wrn 卻不會 ??
, `. }7 J4 Z2 {/ c. A* \誰有相關的經驗嗎 ??
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@W: MO129 :"\projects\dm8606c\rtl\tff256x64.v":932:3:932:8|
Sequential instance ld_tdr_cur_f has been reduced to a combinational gate by constant propagation
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  j: j7 n: c+ z$ }     reg ld_tdr_cur_f;  
* I) e7 t1 g7 s  @. e- U     reg dly_tdr_wrn;
# W7 s! U/ F! C1 E# L   //------------------------
   // delay 1 clk
+ k& X* C$ A0 A0 J6 w& X2 d8 T   //------------------------
   always@(posedge sclk)
   begin
6 U/ r( n/ P2 D  t: ?      ld_tdr_cur_f <=#td1 ld_tdr_cur;
      dly_tdr_wrn  <=#td1 tdr_wrn;
   end
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// 下面是 ld_tdr_cur_f , dly_tdr_wrn 的loading

   always @(posedge sclk)
      if (ld_madr & !wr_nxt_tdr)  
         wr_save_1st <= #td1 wr_counter;
0 g+ F% z7 t. h! i. j+ p      else if (ld_tdr_cur_f)      
, y- T2 Y8 ^# v* S0 {         wr_save_1st <= #td1 wr_save_2nd;
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! b8 a; S8 L7 F  {! t) i: J) P   always @(posedge sclk or negedge rstn)
, c" {0 H6 i/ [) D& E: R1 _      if (!rstn)      
9 x" o2 J: P- }3 ?) X         rst_ff_pt <= #td1 1'b0;
      else
. C4 g+ i) t5 B$ C  Q" A         rst_ff_pt <= #td1 (!tdr_wrn & dly_tdr_wrn & tdr_empty);
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. \: g) f- ~. c  F  b7 z" T   always @(posedge sclk or negedge rstn)
      if (!rstn)      
9 u6 i  P" L, E         rst_ffpt_sync <= #td1 1'b0;
      else if (!tdr_wrn & dly_tdr_wrn & tdr_empty)
         rst_ffpt_sync <= #td1 1'b1;
      else if (rst_ffpt_clr2)  
         rst_ffpt_sync <= #td1 1'b0;

yadog

不清楚要实现什么功能
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但是在写法上有些问题
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& s/ w2 F1 c) S/ Z3 y4 Qif (ld_madr !wr_nxt_tdr)   这句是否笔误？ld_madr ，wr_nxt_tdr是两个信号把？
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7 U( |  ^) y0 X- U% a另外if else if写法均不完备，建议将else项完备

kuhwakimo

是貼上去的時候出現亂碼,更正如下   
//------------------------
) S1 q0 ^& [& [   // save start pointer for 1st pkt
   //------------------------
3 G2 v4 K/ z1 P/ y5 X2 i5 B   always @(posedge sclk)
      if (ld_madr & !wr_nxt_tdr)  
+ w- E: {5 p1 ~         wr_save_1st <= #td1 wr_counter;
4 t+ v$ ?/ m, O4 G) Y$ V      else if (ld_tdr_cur_f)      
         wr_save_1st <= #td1 wr_save_2nd;