Subversion Repositories qaz_libs

// Chuck Benz, Hollis, NH   Copyright (c)2002

//

// The information and description contained herein is the

// property of Chuck Benz.

//

// Permission is granted for any reuse of this information

// and description as long as this copyright notice is

// preserved.  Modifications may be made as long as this

// notice is preserved.

// 11-OCT-2002: updated with clearer messages, and checking decodeout

`timescale 1ns / 1ns

module test_8b10b ;

   reg [29:0]    code8b10b [0:267] ;

   reg [8:0]     testin ;

   reg          dispin ;

   reg [10:0]    i ;

   wire [9:0]    testout ;

   wire         dispout, decodedisp, decodeerr, disperr ;

   wire [8:0]    decodeout ;

   // My data file is 30 columns. Column 1 becomes [29], 2 becomes [28], etc..

   // code[0] is last Column (30)

   // First column, [29] is K indication

   // columns 2:9, [28:21], are data byte, aka 'm' and 'n' of Dm.n

   // columns 10:19, [20:11] are 10b symbol if starting disparity was negative, 0

   // columns 20:29, [10:1] are 10b symbol if starting disparity was positive, 1

   // column 30, [0], is a 1 if symbol results in a disparity flip

   //   0 for a balanced symbol (5 '1's, 5 '0's).

   wire [29:0]   code = code8b10b[i] ;

   wire [9:0]    expect_0_disp = {code[11], code[12], code[13], code[14], code[15],

                                 code[16], code[17], code[18], code[19], code[20]} ;

   wire [9:0]    expect_1_disp = {code[1], code[2], code[3], code[4], code[5],

                                 code[6], code[7], code[8], code[9], code[10]} ;

   reg [1023:0] legal ;  // mark every used 10b symbol as legal, leave rest marked as not

   reg [2047:0] okdisp ; // now mark every used combination of symbol and starting disparity

   reg [8:0]     mapcode [1023:0] ;

   reg [10:0]    codedisp0, codedisp1 ;

   reg [9:0]     decodein ;

   reg          decdispin ;

   integer      errors ;

   encode DUTE (testin, dispin, testout, dispout) ;

   decode DUTD (decodein, decdispin, decodeout, decodedisp, decodeerr, disperr) ;

   always @ (code) testin = code[29:21] ;

   initial begin

      errors = 0 ;

      $readmemb ("8b10b_a.mem", code8b10b) ;

      //$vcdpluson ;

      $dumpvars (0);

      $display ("\n\nFirst, test by trying all 268 (256 Dx.y and 12 Kx.y)") ;

      $display ("valid inputs, with both + and - starting disparity.");

      $display ("We check that the encoder output and ending disparity is correct.");

      $display ("We also check that the decoder matches.");

      for (i = 0 ; i < 268 ; i = i + 1) begin

         // testin = code[29:21] ;

         dispin = 0 ;

         #1

           decodein = testout ;

         decdispin = dispin ;

         #1

//         $display ("%b %b %b %b *%b*", dispin, testin, testout, {dispout, DUTD.disp6a, DUTD.disp6a2, DUTD.disp6a0, DUTD.disp6a2}, decodeout,, decodedisp,, DUTD.k28,, DUTD.disp6b) ;

         if (testout != expect_0_disp)

           $display ("bad code0 %b %b %b %b %b", dispin, testin,  dispout, testout, expect_0_disp) ;

         if (dispout != (dispin ^ code[0]))

           $display ("bad disp0 %b %b %b %b %b", dispin, testin, dispout, testout, (dispin ^ code[0])) ;

         if (0 != (9'b1_1111_1111 & (testin ^ decodeout)))

           $display ("diff in abcdefghk decode, %b %b %b %b %b", dispin, testin,  dispout, testout, decodeout) ;

         if (decodedisp != dispout)

           $display ("diff in decoder disp out, %b %b %b %b %b", dispin, testin,  dispout, testout, decodeout) ;

         if (decodeerr) $display ("decode error asserted improperly, %b %b %b %b %b", dispin, testin,  dispout, testout, decodeout) ;

         if ((testout != expect_0_disp) | decodeerr |

             (dispout != (dispin ^ code[0])) | (decodedisp != dispout))

           errors = errors + 1 ;

         dispin = 1 ;

         #1

         decodein = testout ;

         decdispin = dispin ;

         #1

//         $display ("%b %b %b %b *%b*", dispin, testin, testout, {dispout, DUTD.disp6a, DUTD.disp6a2, DUTD.disp6a0, DUTD.disp6a2, DUTD.fghjp31, DUTD.feqg, DUTD.heqj, DUTD.fghj22, DUTD.fi, DUTD.gi, DUTD.hi, DUTD.ji, DUTD.dispout}, decodeout,, decodedisp,, DUTD.k28,, DUTD.disp6b) ;

         if (testout != expect_1_disp)

           $display ("bad code1 %b %b %b %b %b", dispin, testin, dispout, testout, expect_1_disp) ;

         if (dispout != (dispin ^ code[0]))

           $display ("bad disp1 %b %b %b %b %b", dispin, testin,  dispout, testout, (dispin ^ code[0])) ;

         if (0 != (9'b1_1111_1111 & (testin ^ decodeout)))

           $display ("diff in abcdefghk decode, %b %b %b %b %b", dispin, testin,  dispout, testout, decodeout) ;

         if (decodedisp != dispout)

           $display ("diff in decoder disp out, %b %b %b %b %b", dispin, testin,  dispout, testout, decodeout) ;

         if (decodeerr) $display ("decode error asserted improperly, %b %b %b %b %b", dispin, testin,  dispout, testout, decodeout) ;

         if ((testout != expect_1_disp) | decodeerr |

             (dispout != (dispin ^ code[0])) | (decodedisp != dispout))

           errors = errors + 1 ;

      end

      $display ("%d errors in that testing.\n", errors) ;

      // Now, having verified all legal codes, lets run some illegal codes

      // at the decoder... how to figure illegal codes ?  2048 possible cases,

      // lets mark the OK ones...

      legal = 0 ;

      okdisp = 0 ;

      for (i = 0 ; i < 268 ; i = i + 1) begin

         #1

//         $display ("i=%d: %b %b %d %d %x %x", i, expect_0_disp, expect_1_disp, expect_0_disp, expect_1_disp, expect_0_disp, expect_1_disp) ;

         legal[expect_0_disp] = 1 ;

         legal[expect_1_disp] = 1 ;

         codedisp0 = expect_0_disp ;

         codedisp1 = {1'b1, expect_1_disp} ;

         okdisp[codedisp0] = 1 ;

         okdisp[codedisp1] = 1 ;

         mapcode[expect_0_disp] = code[29:21] ;

         mapcode[expect_1_disp] = code[29:21] ;

      end

      $display ("Now lets test all (legal and illegal) codes into the decoder.");

      $display ("checking all possible decode inputs") ;

      for (i = 0 ; i < 1024 ; i = i + 1) begin

         decodein = i ;

         decdispin = 0 ;

         codedisp1 = 1024 | i ;

         #1

         if (((legal[i] == 0) & (decodeerr != 1)) |

             (legal[i] & (mapcode[i] != decodeout)) |

             (legal[i] & (disperr != !okdisp[i])))

           $display ("10b:%b start disp:%b 8b:%b end disp:%b codevio:%b dispvio:%b known code:%b used disp:",

                     decodein, decdispin, decodeout, decodedisp, decodeerr, disperr, legal[i], okdisp[i]) ;

         if ((legal[i] == 0) & (decodeerr != 1)) $display ("ERR: decoderr should be 1") ;

         if (legal[i] & (mapcode[i] != decodeout)) $display ("ERR: decode output incorrect") ;

         if (legal[i] & (disperr != 1) & !okdisp[i]) $display ("ERR: disp err should be asserted") ;

         else if (legal[i] & (disperr != 0) & okdisp[i])

           $display ("ERR: disp err should not be asserted") ;

         if (((legal[i] == 0) & (decodeerr != 1)) |

             (legal[i] & !disperr & !okdisp[i]) |

             (legal[i] & (mapcode[i] != decodeout)) |

             (legal[i] & disperr & okdisp[i]))

           errors = errors + 1 ;

         decdispin = 1 ;

         #1

         if (((legal[i] == 0) & (decodeerr != 1)) |

             (legal[i] & (mapcode[i] != decodeout)) |

             (legal[i] & (disperr != !okdisp[i|1024])))

           $display ("10b:%b start disp:%b 8b:%b end disp:%b codevio:%b dispvio:%b known code:%b used disp:",

                     decodein, decdispin, decodeout, decodedisp, decodeerr, disperr, legal[i], okdisp[i|1024]) ;

         if ((legal[i] == 0) & (decodeerr != 1)) $display ("ERR: decoderr should be 1") ;

         if (legal[i] & (mapcode[i] != decodeout)) $display ("ERR: decode output incorrect") ;

         if (legal[i] & (disperr != 1) & !okdisp[i|1024]) $display ("ERR: disp err should be asserted") ;

         else if (legal[i] & (disperr != 0) & okdisp[i|1024])

           $display ("ERR: disp err should not be asserted") ;

         if (((legal[i] == 0) & (decodeerr != 1)) |

             (legal[i] & !disperr & !okdisp[i|1024]) |

             (legal[i] & (mapcode[i] != decodeout)) |

             (legal[i] & disperr & okdisp[i|1024]))

           errors = errors + 1 ;

      end // for (i = 0 ; i < 1024 ; i = i + 1)

      $display ("\nDone testing decoder.\n") ;

      $display ("Total error count: %d", errors);

      if (errors == 0) $display ("Congratulations!\n");

      $finish ;

   end // initial begin

endmodule