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cse141L-project/RTL/program1_tb1.sv
Arthur Lu 935864ad9c fix bug in PC jump target calculation,
fix bug in RegFile input width,
fix control logic bug with INC/DEC,
change assembler output format,
change programs to use d0 as space char value
2022-08-14 13:44:51 -07:00

156 lines
8.4 KiB
Systemverilog

// program1_tb
// testbench for programmable message encryption (Program #1)
// CSE141L
// runs program 1 (encrypt a message)
module program1_tb () ;
// DUT interface -- four one-bit wires, three to DUT, one from
bit clk , // advances simulation step-by-step
init = 1'b1 , // init (reset) command to DUT
start = 1'b1 ; // request (start program) command to DUT
wire done ; // acknowledge (program done) flag returned by DUT
// test bench parameters
logic[7:0] pre_length ; // number of space char. before message itself, sent to data_mem[61]
logic[7:0] message1[54] , // original raw message, in binary, up to 54 characters in length
msg_padded1[64], // original message, plus pre- and post-padding w/ ASCII spaces
msg_crypto1[64]; // encrypted message returned by DUT
logic[7:0] lfsr_ptrn , // choses one of 9 maximal length 7-tap shift reg. patterns
LFSR_ptrn[9] , // the 9 candidate maximal-length 7-bit LFSR tap ptrns themselves
lfsr1[64] , // states of program 1 encrypting LFSR
LFSR_init ; // one of 127 possible NONZERO starting states for encrypting LFSR
int score ; // count of correctly 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
// 55 characters in length
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 = " f A joke is a very serious thing."; // as well)
// string str1 = " Ajoke "; //
// string str1 = "@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@";
// string str1 = " Knowledge comes, but wisdom lingers. "; //
// displayed encrypted string will go here:
string str_enc1[64]; // program 1 desired output will go here
int strlen; // length of incoming message string itself, before padding
logic[3:0] pt_no; // select LFSR pattern, index value 0 through 8
int file_no; // output file tag (set to 1 for write to console/transcript)
// the 9 possible 7-tap maximal-length feedback tap patterns from which to choose
assign LFSR_ptrn[0] = 8'h60; // (0)110_0000
assign LFSR_ptrn[1] = 8'h48;
assign LFSR_ptrn[2] = 8'h78;
assign LFSR_ptrn[3] = 8'h72;
assign LFSR_ptrn[4] = 8'h6A;
assign LFSR_ptrn[5] = 8'h69;
assign LFSR_ptrn[6] = 8'h5C;
assign LFSR_ptrn[7] = 8'h7E; // (0)111_1110
assign LFSR_ptrn[8] = 8'h7B;
always_comb begin
pt_no = 8;//$random; // or select a specific pattern ([0] and [1] are simplest to debug
if(pt_no>8) pt_no[3] = 0; // restrict pt_no to 0 through 8
lfsr_ptrn = LFSR_ptrn[pt_no]; // look up and engage the selected pattern; to data_mem[62]
end
// now select a starting LFSR state -- any nonzero value will do
always_comb begin
LFSR_init = 'b1;//$random>>2; // or set a specific value, such as 7'b1, for easier debug
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 = 10;//$random>>10 ; // number of space characters ahead of message; the >>10 changes the random value
if(pre_length < 10) pre_length = 10; // prevents pre_length < 10
else if(pre_length > 26) 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
//***** 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
// to display to console, change this line to file_no = 'b1;
file_no = 'b1; // display to console instead of file
// file_no = $fopen("msg_enocder_out.txt","w"); // create your output file
#0ns strlen = str1.len; // length of string 1 (# characters between " ")
if(strlen>54) strlen = 54; // clip message at 54 characters
// 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,"pt_no = %d",pt_no);
$fdisplay(file_no,"LFSR_ptrn = 0x%h, LFSR_init = 0x%h",lfsr_ptrn,LFSR_init);
// will subtract 0x20 from each preamble and each message character
for(int j=0; j<64; j++) // pre-fill message_padded with ASCII space characters
msg_padded1[j] = 8'h20; //
for(int l=0; l<strlen; l++) // overwrite up to 54 of these spaces w/ message itself
msg_padded1[pre_length+l] = str1[l]; // test bench does the -0x20 offset now
// compute and store the LFSR sequence
for (int ii=0;ii<63;ii++)
lfsr1[ii+1] = {(lfsr1[ii][5:0]),(^(lfsr1[ii]&lfsr_ptrn))};
// encrypt the message character-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]-32) ^ lfsr1[i]);
msg_crypto1[i][7] = 'b0;//^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 (<8'h20)
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
// ***** 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'h0; // pad memory w/ ASCII space characters
for(int m=0; m<strlen; m++)
dut.DM.core[m] = (str1[m]-8'h20); // 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 permissible patterns)
dut.DM.core[63] = LFSR_init; // LFSR starting state (nonzero)
#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
// #2000ns;
#10ns $fdisplay(file_no,"");
$fdisplay(file_no,"program 1:");
// ***** reads your results and compares to test bench
// ***** use your instance name for data memory and its internal core *****
// the +'h20 restores the -32 bias, for better display visuals
for(int n=0; n<64; n++) begin
if(msg_crypto1[n]==dut.DM.core[n+64]) begin
$fdisplay(file_no,"%d bench msg: %s %h dut msg: %h",
n, msg_crypto1[n][6:0]+8'h20, msg_crypto1[n], dut.DM.core[n+64]);
score++;
end
else
$fdisplay(file_no,"%d bench msg: %s %h dut msg: %h OOPS!",
n, msg_crypto1[n][6:0]+8'h20, msg_crypto1[n], dut.DM.core[n+64]);
end
$fdisplay(file_no,"score = %d/64",score);
#20ns $fclose(file_no);
#20ns $stop;
end
always begin // continuous loop
#5ns clk = 1; // clock tick
#5ns clk = 0; // clock tock
end
endmodule