From bb0897a4099b48b6477e1b17de69ccd6f7c2cad8 Mon Sep 17 00:00:00 2001
From: Konstantin Pavlov <pavlovconst@gmail.com>
Date: Tue, 23 May 2023 11:49:24 +0300
Subject: [PATCH] Fix clog usage in pulse_stretch.sv

---
 pulse_stretch.sv | 95 +++++++++++++++++++++++++-----------------------
 1 file changed, 50 insertions(+), 45 deletions(-)

diff --git a/pulse_stretch.sv b/pulse_stretch.sv
index 714f028..4785df7 100644
--- a/pulse_stretch.sv
+++ b/pulse_stretch.sv
@@ -1,13 +1,15 @@
 //--------------------------------------------------------------------------------
 // pulse_stretch.sv
+// published as part of https://github.com/pConst/basic_verilog
 // Konstantin Pavlov, pavlovconst@gmail.com
 //--------------------------------------------------------------------------------
 
 // INFO --------------------------------------------------------------------------------
 // Pulse stretcher/extender module
-//   this implementftion uses a simple delay line or counter to stretch pulses
-//   WIDTH parameter sets output pulse width
-//   if you need variable output poulse width, see pulse_gen.sv module
+//
+//  - this implementftion uses a simple delay line or counter to stretch pulses
+//  - WIDTH parameter sets output pulse width
+//  - if you need variable output poulse width, see pulse_gen.sv module
 
 
 /* --- INSTANTIATION TEMPLATE BEGIN ---
@@ -24,6 +26,7 @@ pulse_stretch #(
 
 --- INSTANTIATION TEMPLATE END ---*/
 
+
 module pulse_stretch #( parameter
   WIDTH = 8,
   USE_CNTR = 0      // ==0  - stretcher is implemented on delay line
@@ -37,55 +40,57 @@ module pulse_stretch #( parameter
 );
 
 
-localparam CNTR_WIDTH = $clog2(WIDTH) + 1;
+  localparam CNTR_W = $clog2(WIDTH+1);
 
-generate
+  generate
+    //==========================================================================
+    if( WIDTH == 0 ) begin
+      assign out = 0;
 
-  if ( WIDTH == 0 ) begin
-    assign out = 0;
-
-  end else if( WIDTH == 1 ) begin
-    assign out = in;
-
-  end else begin
-    if( USE_CNTR == '0 ) begin
-      // delay line
-
-      logic [WIDTH-1:0] shifter = '0;
-      always_ff @(posedge clk) begin
-        if( ~nrst ) begin
-          shifter[WIDTH-1:0] <= '0;
-        end else begin
-          // shifting
-          shifter[WIDTH-1:0] <= {shifter[WIDTH-2:0],in};
-        end // nrst
-      end // always
-
-      assign out = (shifter[WIDTH-1:0] != '0);
+    //==========================================================================
+    end else if( WIDTH == 1 ) begin
+      assign out = in;
 
+    //==========================================================================
     end else begin
-      // counter
+      if( USE_CNTR == '0 ) begin
+        // delay line
 
-      logic [CNTR_WIDTH-1:0] cntr = '0;
-      always_ff @(posedge clk) begin
-        if( ~nrst ) begin
-          cntr[CNTR_WIDTH-1:0] <= '0;
-        end else begin
-          if( in ) begin
-            // setting counter
-            cntr[CNTR_WIDTH-1:0] <= CNTR_WIDTH'(WIDTH);
-          end else if( out ) begin
-            // decrementing counter
-            cntr[CNTR_WIDTH-1:0] <= cntr[CNTR_WIDTH-1:0] - 1'b1;
-          end
-        end // nrst
-      end // always
+        logic [WIDTH-1:0] shifter = '0;
+        always_ff @(posedge clk) begin
+          if( ~nrst ) begin
+            shifter[WIDTH-1:0] <= '0;
+          end else begin
+            // shifting
+            shifter[WIDTH-1:0] <= {shifter[WIDTH-2:0],in};
+          end // nrst
+        end // always
 
-      assign out = (cntr[CNTR_WIDTH-1:0] != '0);
+        assign out = (shifter[WIDTH-1:0] != '0);
 
-    end
-  end // if WIDTH
-endgenerate
+      end else begin
+        // counter
+
+        logic [CNTR_W-1:0] cntr = '0;
+        always_ff @(posedge clk) begin
+          if( ~nrst ) begin
+            cntr[CNTR_W-1:0] <= '0;
+          end else begin
+            if( in ) begin
+              // setting counter
+              cntr[CNTR_W-1:0] <= CNTR_W'(WIDTH);
+            end else if( out ) begin
+              // decrementing counter
+              cntr[CNTR_W-1:0] <= cntr[CNTR_W-1:0] - 1'b1;
+            end
+          end // nrst
+        end // always
+
+        assign out = (cntr[CNTR_W-1:0] != '0);
+
+      end
+    end // if WIDTH
+  endgenerate
 
 
 endmodule