Converted flops to synchronous reset now that reset signal is synchronized

wally-pipelined/src/generic/flop/flopenl.sv

@@ -25,14 +25,14 @@
 
 `include "wally-config.vh"
 
-// flop with enable, asynchronous load
+// flop with enable, synchronous load
 module flopenl #(parameter WIDTH = 8, parameter type TYPE=logic [WIDTH-1:0]) (
   input  logic clk, load, en,
   input  TYPE d,
   input  TYPE val,
   output TYPE q);
 
-  always_ff @(posedge clk, posedge load)
+  always_ff @(posedge clk)
     if (load)    q <= #1 val;
     else if (en) q <= #1 d;
 endmodule

wally-pipelined/src/generic/flop/flopenr.sv

@@ -25,13 +25,13 @@
 
 `include "wally-config.vh"
 
-// flop with enable, asynchronous reset
+// flop with enable, synchronous reset
 module flopenr #(parameter WIDTH = 8) (
   input  logic             clk, reset, en,
   input  logic [WIDTH-1:0] d, 
   output logic [WIDTH-1:0] q);
 
-  always_ff @(posedge clk, posedge reset)
+  always_ff @(posedge clk)
     if (reset)   q <= #1 0;
     else if (en) q <= #1 d;
 endmodule

wally-pipelined/src/generic/flop/flopenrc.sv

@@ -25,13 +25,13 @@
 
 `include "wally-config.vh"
 
-// flop with enable, asynchronous reset, synchronous clear
+// flop with enable, synchronous reset, enabled clear
 module flopenrc #(parameter WIDTH = 8) (
   input  logic             clk, reset, clear, en,
   input  logic [WIDTH-1:0] d, 
   output logic [WIDTH-1:0] q);
 
-  always_ff @(posedge clk, posedge reset)
+  always_ff @(posedge clk) 
     if (reset)   q <= #1 0;
     else if (en) 
       if (clear) q <= #1 0;

wally-pipelined/src/generic/flop/flopens.sv

@@ -25,13 +25,13 @@
 
 `include "wally-config.vh"
 
-// flop with enable, asynchronous set
+// flop with enable, synchronous set
 module flopens #(parameter WIDTH = 8) (
   input  logic             clk, set, en,
   input  logic [WIDTH-1:0] d, 
   output logic [WIDTH-1:0] q);
 
-  always_ff @(posedge clk, posedge set)
+  always_ff @(posedge clk) 
     if (set)   q <= #1 1;
     else if (en) q <= #1 d;
 endmodule

wally-pipelined/src/generic/flop/flopr.sv

@@ -25,13 +25,13 @@
 
 `include "wally-config.vh"
 
-// flop with asynchronous reset
+// flop with synchronous reset
 module flopr #(parameter WIDTH = 8) ( 
   input  logic             clk, reset,
   input  logic [WIDTH-1:0] d, 
   output logic [WIDTH-1:0] q);
 
-  always_ff @(posedge clk, posedge reset)
+  always_ff @(posedge clk)
     if (reset) q <= #1 0;
     else       q <= #1 d;
 endmodule

wally-pipelined/src/generic/flop/floprc.sv

@@ -25,7 +25,7 @@
 
 `include "wally-config.vh"
 
-// flop with asynchronous reset, synchronous clear
+// flop with synchronous reset, synchronous clear
 module floprc #(parameter WIDTH = 8) (
   input  logic clk,
   input  logic reset,
@@ -33,9 +33,7 @@ module floprc #(parameter WIDTH = 8) (
   input  logic [WIDTH-1:0] d, 
   output logic [WIDTH-1:0] q);
 
-  always_ff @(posedge clk, posedge reset)
+  always_ff @(posedge clk)
-    if (reset) q <= #1 0;
+    if (reset | clear ) q <= #1 0;
-    else       
+    else                q <= #1 d;
-      if (clear) q <= #1 0;
-      else       q <= #1 d;
 endmodule

wally-pipelined/src/generic/flop/synchronizer.sv

@@ -0,0 +1,41 @@
+///////////////////////////////////////////
+// synchronizer.sv
+//
+// Written: David_Harris@hmc.edu 25 October 2021
+// Modified: 
+//
+// Purpose: Two-stage flip-flop synchronizer
+// 
+// A component of the Wally configurable RISC-V project.
+// 
+// Copyright (C) 2021 Harvey Mudd College & Oklahoma State University
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation
+// files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, 
+// modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software 
+// is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES 
+// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS 
+// BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT 
+// OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+///////////////////////////////////////////
+
+`include "wally-config.vh"
+
+// ordinary flip-flop
+module synchronizer ( 
+  input  logic clk,
+  input  logic d, 
+  output logic q);
+
+  logic mid;
+
+  always_ff @(posedge clk) begin
+    mid <= #1 d;
+    q <= #1 d;
+  end
+endmodule
+