diff --git a/RTL/program3_tb.sv b/RTL/program3_tb.sv
index 999173c..a71a19c 100644
--- a/RTL/program3_tb.sv
+++ b/RTL/program3_tb.sv
@@ -2,155 +2,178 @@
 // testbench for programmable message decryption, space removal (Program #3)
 // CSE141L  
 // runs program 2 (decrypt a message), but with corruption
-module program3_tb ();
-  	logic clk = 1'b0; // advances simulation step-by-step
-	logic init = 1'b1; // init (reset) command to DUT
-	logic start = 1'b1; // req (start program) command to DUT
-	wire done; // done flag returned by DUT
-	logic[3:0] pre_length; // space char. bytes before first char. in message  
-	logic[7:0] message1[49]; // original raw message, in binary
-	logic[7:0] msg_padded1[80]; // original message, plus pre- and post-padding w/ ASCII spaces
-	logic[7:0] msg_crypto1[64]; // encrypted message according to the DUT
-  	logic[6:0] lfsr_ptrn; // chosen one of 9 maximal length 7-tap shift reg. ptrns
-	logic[6:0] LFSR_ptrn[9]; // the 9 candidate maximal-length 7-bit LFSR tap ptrns
-	logic[6:0] lfsr1[64]; // states of program 1 encrypting LFSR
-	logic[6:0] LFSR_init; // one of 127 possible NONZERO starting states
-	int score; // count of correct encyrpted characters
+module decrypt_depad_tb ()        ;
+// DUT interface
+  logic      clk   = 1'b0   ,      // advances simulation step-by-step
+             init  = 1'b1   ,      // init (reset) command to DUT
+             start = 1'b1   ;      // req (start program) command to DUT
+  wire       done           ;      // done flag returned by DUT
+// test bench parameters
+  logic[3:0] pre_length     ;      // space char. bytes before first char. in message  
+  logic[7:0] message1[49]   ,      // original raw message, in binary
+             msg_padded1[80],      // original message, plus pre- and post-padding w/ ASCII spaces
+             msg_crypto1[64];      // encrypted message according to the DUT
+  logic[6:0] lfsr_ptrn      ,      // chosen one of 9 maximal length 7-tap shift reg. ptrns
+             LFSR_ptrn[9]   ,      // the 9 candidate maximal-length 7-bit LFSR tap ptrns
+             lfsr1[64]      ,      // states of program 1 encrypting LFSR
+             LFSR_init      ;      // one of 127 possible NONZERO starting states
+  int        score          ;      // count of correct encyrpted characters
+// our original American Standard Code for Information Interchange message follows
+// note in practice your design should be able to handle ANY ASCII string that is
+//  restricted to characters between space (0x20) and script f (0x9f) and shorter than 
+//  53 characters in length
+// *** No more than 24 leading space characters, including preamble. ***
+//    string     str1 = 
+//  string     str1  = "Mr. Watson, come here. I want to see you.";     // sample program 1 input
+//  string     str1  = " Knowledge comes, but wisdom lingers.    ";   // alternative inputs
+//  string     str1  = "  01234546789abcdefghijklmnopqrstuvwxyz. ";   //   (make up your own,
+//  string     str1  = "      A joke is a very serious thing.";   // 	as well)
+  string     str1  = "          Ajok          ";   // 
+//	string     str1  = "@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@";
+//	string     str1  = "``@@```@@@````@@@@````@@@@@";
+//  string     str1  = " Knowledge comes, but wisdom lingers.    ";   // 
 
-	// our original American Standard Code for Information Interchange message follows
-	// note in practice your design should be able to handle ANY ASCII string that is
-	//  restricted to characters between space (0x20) and script f (0x9f) and shorter than 
-	//  53 characters in length
-	string str1 = "    four score and seven years ago...";
-
-	// displayed encrypted string will go here:
-	string str_enc1[64]; // program 1 desired output will go here
-	int strlen; // incoming string length 
-	int pt_no; // select LFSR pattern, value 0 through 8
-	int file_no; // write to file
-	int space; // counts leading space characters in message
-	logic [5:0] flipper; // corruptor -- bit flip
-	logic [79:0] flipped = 80'b0; // tracks which word got a bit flipped
-
-	// the 9 possible maximal-length feedback tap patterns from which to choose
-	assign LFSR_ptrn[0] = 7'h60;	   // 110_0000  
-	assign LFSR_ptrn[1] = 7'h48;
-	assign LFSR_ptrn[2] = 7'h78;
-	assign LFSR_ptrn[3] = 7'h72;
-	assign LFSR_ptrn[4] = 7'h6A;
-	assign LFSR_ptrn[5] = 7'h69;
-	assign LFSR_ptrn[6] = 7'h5C;
-	assign LFSR_ptrn[7] = 7'h7E;
-	assign LFSR_ptrn[8] = 7'h7B;
-  
-	always_comb begin
-		pt_no = $urandom_range(0, 8);
-		if(pt_no>8) pt_no[3] = 0; // restrict pt_no to 0 through 8
-		lfsr_ptrn = LFSR_ptrn[pt_no]; // look up and engage the selected pattern; to data_mem[62]
-	end
-
-	// now select a starting LFSR state -- any nonzero value will do
-	always_comb begin					   
-		LFSR_init = $urandom;
-		if(!LFSR_init) LFSR_init = 7'b1; // prevents illegal starting state = 7'b0; 
-	end
-
-	// set preamble length for the program run (always > 9 but < 26)
-	always_comb begin
-		pre_length = $urandom_range(10, 26);
-		if(pre_length < 10) pre_length = 10; // prevents pre_length < 10
-		else if(pre_length > 26) pre_length = 26; // prevets pre_length > 26
-	end
-
-	// ***** instantiate your own top level design here *****
-	top_level dut(
-		.clk(clk), // input: use your own port names, if different
-		.init(init), // input: some prefer to call this ".reset"
-		.req(start), // input: launch program
-		.ack(done) // output: "program run complete"
-	);
-
-  	initial begin
-		file_no = 'b1;		 // create your output file
-		#0ns strlen = str1.len;       // length of string 1 (# characters between " ")
-		if(strlen>52) strlen = 52;          // clip message at 52 characters
-    	for(space=0;space<24;space++)		// count leading spaces in message
-			if(str1[space]==8'h20) continue;
-			else break;
-
-		// program 1 -- precompute encrypted message
-		lfsr1[0]     = LFSR_init;           // any nonzero value (zero may be helpful for debug)
-		$fdisplay(file_no,"run encryption program; original message = ");
-		$fdisplay(file_no,"%s",str1);       // print original message in transcript window
-		$fdisplay(file_no,"LFSR_ptrn = 0x%h, LFSR_init = 0x%h, pre_length: %d",lfsr_ptrn,LFSR_init,pre_length);
-		for(int j=0; j<80; j++)            // pre-fill message_padded with ASCII space characters
-			msg_padded1[j] = 8'h20;          //   
-		for(int l=0; l<strlen; l++)        // overwrite up to 49 of these spaces w/ message itself
-			msg_padded1[l+pre_length] = str1[l];  
-		// compute the LFSR sequence
-		for (int ii=0;ii<63;ii++)
-			lfsr1[ii+1] = {(lfsr1[ii][5:0]),(^(lfsr1[ii]&lfsr_ptrn))};
-
-		// encrypt the message charater-by-character, then prepend the parity
-		// testbench will change on falling clocks to avoid race conditions at rising clocks
-		for (int i=0; i<64; i++) begin
-			msg_crypto1[i]        = (msg_padded1[i] ^ lfsr1[i]);
-			msg_crypto1[i][7]     = ^msg_crypto1[i][6:0];       // prepend parity bit into MSB
-			$fdisplay(file_no,"i=%d, msg_pad=0x%h, lfsr=%b msg_crypt w/ parity = 0x%h", i,msg_padded1[i],lfsr1[i],msg_crypto1[i]);
-			str_enc1[i]           = string'(msg_crypto1[i][6:0]);
-		end
-		$fdisplay(file_no,"encrypted string =  "); 
-		for(int jj=0; jj<64; jj++)
-			$fwrite(file_no,"%s",str_enc1[jj]);
-		$fdisplay(file_no,"\n");
-
-		// run encryption program first to know what to decrypt
-		// ***** load operands into your data memory *****
-		// ***** use your instance name for data memory and its internal core *****
-		for(int m=0; m<24; m++)             // load first 24 characters of encrypted message into data memory
-			dut.DM.core[m+64] = msg_crypto1[m];
-		for(int n=24; n<64; n++) begin	  	// load subsequent, possibly corrupt, encrypted message into data memory
-			// set flipper = 8 or higher to disable bit corruption
-	  		flipper = $random;//$random;                // value between 0 and 63, inclusive
-      		dut.DM.core[n+64] = msg_crypto1[n]^(1<<flipper);
-      		if(flipper<8) flipped[n]=1;
-		end
-
-		#20ns init  = 1'b0;				  // suggestion: reset = 1 forces your program counter to 0
-		#10ns start = 1'b0; 			  //   request/start = 1 holds your program counter 
-		#60ns;                            // wait for 6 clock cycles of nominal 10ns each
-		wait(done);                       // wait for DUT's ack/done flag to go high
-		#10ns $fdisplay(file_no,"");
-		$fdisplay(file_no,"program 3:");
-
-		// ***** reads your results and compares to test bench
-		// ***** use your instance name for data memory and its internal core *****
-		for(int n=0; n<64; n++)	begin
-			if(flipped[n+pre_length+space]) begin
-				if(dut.DM.core[n][7]) begin
-					$fdisplay(file_no, "error successfully flagged");
-					score++;
-				end 
-				else begin
-					$fdisplay(file_no, "failed to flag error");
-				end
-			end
-			else if({flipped[n+pre_length+space],msg_padded1[n+pre_length+space][6:0]} == dut.DM.core[n])	begin
-				$fdisplay(file_no,"%d bench msg: %s %h dut msg: %h", n, msg_padded1[n+pre_length+space][6:0], msg_padded1[n+pre_length+space], dut.DM.core[n]);
-				score++;
-			end
-			else
-				$fdisplay(file_no,"%d bench msg: %s %h dut msg: %h  OOPS!", n, msg_padded1[n+pre_length+space][6:0], msg_padded1[n+pre_length+space], dut.DM.core[n]);
-		end
-
-		$fdisplay(file_no,"score = %d/64",score);
-		#20ns $fclose(file_no);
-		#20ns $stop;
+// displayed encrypted string will go here:
+  string     str_enc1[64];         // program 1 desired output will go here
+  int strlen;                      // incoming string length 
+  int pt_no;                       // select LFSR pattern, value 0 through 8
+  int file_no;                     // write to file
+  int space;                       // counts leading space characters in message
+  logic[5:0] flipper; 			   // corruptor -- bit flip
+  logic[79:0] flipped = 80'b0;	   // tracks which word got a bit flipped
+// the 8 possible maximal-length feedback tap patterns from which to choose
+  assign LFSR_ptrn[0] = 7'h60;	   // 110_0000       
+  assign LFSR_ptrn[1] = 7'h48;	   // 100_1000
+  assign LFSR_ptrn[2] = 7'h78;
+  assign LFSR_ptrn[3] = 7'h72;
+  assign LFSR_ptrn[4] = 7'h6A;
+  assign LFSR_ptrn[5] = 7'h69;
+  assign LFSR_ptrn[6] = 7'h5C;
+  assign LFSR_ptrn[7] = 7'h7E;
+  assign LFSR_ptrn[8] = 7'h7B;
+  always_comb begin
+    pt_no = 0; //$random>>22;      // or pick a specific one
+    if(pt_no>8) pt_no[3] = 1'b0;    // restrict to 0 through 8 (our legal patterns)
+    lfsr_ptrn = LFSR_ptrn[pt_no];  // engage the selected pattern
+  end    
+// now select a starting LFSR state -- any nonzero value will do
+  always_comb begin					   
+    LFSR_init = 7'b1;//$random>>2;          // or set a value, such as 7'b1, for debug
+    if(!LFSR_init) LFSR_init = 7'b1; // prevents illegal starting state = 7'b0; 
   end
 
-	always begin     // continuous loop
-		#5ns clk = 1;  // clock tick
-		#5ns clk = 0;  // clock tock
+// set preamble lengths for the program  (always > 9 but < 16)
+  always_comb begin
+    pre_length = 10;//$random>>10 ;             // program 1 run
+    if(pre_length < 10) pre_length = 10;   // prevents pre_length < 10
+    if(pre_length > 15) pre_length = 15;
+  end
+
+// ***** instantiate your own top level design here *****
+  top_level dut(
+    .clk     (clk  ),   // input: use your own port names, if different
+    .init    (init ),   // input: some prefer to call this ".reset"
+    .req     (start),   // input: launch program
+    .ack     (done )    // output: "program run complete"
+  );
+
+  initial begin
+//***** pre-load your instruction ROM here or inside itself	*****
+//    $readmemb("encoder.bin", dut.instr_rom.rom);
+// you may also pre-load desired constants, etc. into
+//   your data_mem here -- the upper addresses are reserved for your use
+//    dut.data_mem.DM[128]=8'hfe;   //whatever constants you want	
+    file_no = 1;	 // write to transcript
+//    file_no = $fopen("msg_decoder_out.txt");		 // create your output file
+    #0ns strlen = str1.len;       // length of string 1 (# characters between " ")
+    if(strlen>52) strlen = 52;          // clip message at 52 characters
+    for(space=0;space<24;space++)		// count leading spaces in message
+	  if(str1[space]==8'h20) continue;
+	  else break;
+// program 1 -- precompute encrypted message
+    lfsr1[0]     = LFSR_init;           // any nonzero value (zero may be helpful for debug)
+    $fdisplay(file_no,"run encryption program; original message = ");
+    $fdisplay(file_no,"%s",str1);       // print original message in transcript window
+    $fdisplay(file_no,"LFSR_ptrn = 0x%h, LFSR_init = 0x%h, pre_length: %d",lfsr_ptrn,LFSR_init,pre_length);
+	$fdisplay(file_no,"pt_no = %d",pt_no);
+
+// will subtract 0x20 from each preamble and messge character to fit into 7 bits
+    for(int j=0; j<80; j++)            // pre-fill message_padded with ASCII space characters
+      msg_padded1[j] = 8'h20;          //   
+    for(int l=0; l<strlen; l++)        // overwrite up to 49 of these spaces w/ message itself
+      msg_padded1[l+pre_length] = str1[l];  
+// compute the LFSR sequence
+    for (int ii=0;ii<63;ii++)
+      lfsr1[ii+1] = {(lfsr1[ii][5:0]),(^(lfsr1[ii]&lfsr_ptrn))};
+
+// encrypt the message charater-by-character, then prepend the parity
+//  testbench will change on falling clocks to avoid race conditions at rising clocks
+    for (int i=0; i<64; i++) begin
+      msg_crypto1[i]        = ((msg_padded1[i]-'h20) ^ lfsr1[i]);
+	  msg_crypto1[i][7]     = 0;//^msg_crypto1[i][6:0];       // prepend parity bit into MSB
+      $fdisplay(file_no,"i=%d, msg_pad=0x%h, lfsr=%b msg_crypt w/ parity = 0x%h",
+         i,msg_padded1[i],lfsr1[i],msg_crypto1[i]);
+//for display purposes only, add 8'h20 to avoid nonprintable characters
+      str_enc1[i]           = string'(msg_crypto1[i][6:0]+'h20);
+    end
+	$fdisplay(file_no,"encrypted string =  "); 
+	for(int jj=0; jj<64; jj++)
+      $fwrite(file_no,"%s",(str_enc1[jj]));
+    $fdisplay(file_no,"\n");
+
+// run encryption program first to know what to decrypt
+// ***** load operands into your data memory *****
+// ***** use your instance name for data memory and its internal core *****
+//    for(int m=0; m<61; m++)
+//	  dut.DM.core[m] = 8'h20;         // pad memory w/ ASCII space characters
+//    for(int m=0; m<strlen; m++)
+//      dut.DM.core[m] = str1[m];       // overwrite/copy original string into device's data memory[0:strlen-1]
+//    dut.DM.core[61] = pre_length;     // number of bytes preceding message
+//    dut.DM.core[62] = lfsr_ptrn;      // LFSR feedback tap positions (9 possible ptrns)
+//    dut.DM.core[63] = LFSR_init;      // LFSR starting state (nonzero)
+    for(int m=0; m<24; m++)             // load first 24 characters of encrypted message into data memory
+      dut.DM.core[m+64] = msg_crypto1[m];
+    for(int n=24; n<64; n++) begin	  	// load subsequent, possibly corrupt, encrypted message into data memory
+// set flipper = 8 or higher to disable bit corruption
+	  flipper = 8;//$random;                // value between 0 and 63, inclusive
+      dut.DM.core[n+64] = msg_crypto1[n]^(1<<flipper);
+      if(flipper<8) flipped[n]=1;
 	end
+    #20ns init  = 1'b0;				  // suggestion: reset = 1 forces your program counter to 0
+	#10ns start = 1'b0; 			  //   request/start = 1 holds your program counter 
+    #60ns;                            // wait for 6 clock cycles of nominal 10ns each
+    wait(done);                       // wait for DUT's ack/done flag to go high
+    #10ns $fdisplay(file_no,"");
+    $fdisplay(file_no,"program 3:");
+// ***** reads your results and compares to test bench
+// ***** use your instance name for data memory and its internal core *****
+    for(int n=0; n<(64-pre_length-space); n++)	begin
+      if(flipped[n+pre_length+space]) begin
+        if(dut.DM.core[n][7]) begin
+          $fdisplay(file_no, "error successfully flagged");
+          score++;
+        end else begin
+          $fdisplay(file_no, "failed to flag error");
+        end
+      end
+//      else if({flipped[n+pre_length+space],msg_padded1[n+pre_length+space][6:0]}
+        else if(msg_padded1[n+pre_length+space] == dut.DM.core[n]+32)	begin
+        $fdisplay(file_no,"%d bench msg: %s %h dut msg: %h",
+          n, msg_padded1[n+pre_length+space][6:0], msg_padded1[n+pre_length+space], dut.DM.core[n]);
+        score++;
+      end
+      else
+        $fdisplay(file_no,"%d bench msg: %s %h dut msg: %h  OOPS!",
+          n, msg_padded1[n+pre_length+space][6:0], msg_padded1[n+pre_length+space], dut.DM.core[n]);
+    end
+    $fdisplay(file_no,"score = %0d/%0d",score,64-pre_length-space);
+    #20ns $fclose(file_no);
+    #20ns $stop;
+  end
+
+always begin     // continuous loop
+  #5ns clk = 1;  // clock tick
+  #5ns clk = 0;  // clock tock
+end
 
 endmodule
\ No newline at end of file