Subversion Repositories ssbcc

#!/usr/bin/gawk

# Copyright 2012, Sinclair R.F., Inc.

#

# Parse the output of the Verilog test bench to ensure the signals transmit

# "Hello World!" and the proper baud and number of stop bits.

function abs(a) {

  return (a>=0) ? a : -a;

}

function append_state() {

  dt = t_cur-state[ix,"t_last"];

  nbits = int(dt/dtBaud);

  if (dt-nbits*dtBaud > 0.5*dtBaud) ++nbits;

  dt -= nbits*dtBaud;

  for (jx=0; jx<nbits; ++jx)

    state[ix,"cur"] = state[ix,"cur"] state[ix,"last"];

}

function convert_state(_v) {

  _v = 0;

  for (jx=0; jx<8; ++jx) {

    _v /= 2;

    _v += strtonum(substr(state[ix,"cur"],2+jx,1))*0x80;

  }

  state[ix,"cur"] = "";

  return sprintf("%c",_v);

}

BEGIN {

  first = 1;

  for (ix=1; ix<=3; ++ix) {

    state[ix,"mode"] = -1;

    state[ix,"msg"] = "";

    state[ix,"nStop"] = 1;

    state[ix,"last"] = 1;

  }

  state[3,"nStop"] = 2;

  dtBaud = 1./115200;

  dtTol = 1./100e6/2;

}

{

  t_cur = $1/1.e9;

  if (first > 0) {

    --first;

    for (ix=1; ix<=3; ++ix)

      state[ix,"t_last"] = t_cur;

    next;

  }

  for (ix=1; ix<=3; ++ix) {

    this = $(ix+2);

    if (this == state[ix,"last"])

      continue;

    if (state[ix,"mode"] == -1) {

      if (this != "0") {

        print "Missing start bit at line",FNR > "/dev/stderr";

        exit(1);

      } else {

        state[ix,"t_last"] = t_cur;

        state[ix,"mode"] = 0;

        state[ix,"last"] = "0";

        state[ix,"cur"] = "";

      }

    } else {

      append_state();

      if (length(state[ix,"cur"]) < 9+state[ix,"nStop"]) {

        if (abs(dt)>dtTol*nbits) {

          print "Baud rate out of tolerance at line",FNR > "/dev/stderr";

          exit(1);

        }

      } else if (length(state[ix,"cur"]) == 9+state[ix,"nStop"]) {

        if (dt < -dtTol*nbits) {

          print "Baud rate out of tolerance at line",FNR > "/dev/stderr";

          exit(1);

        }

        state[ix,"msg"] = state[ix,"msg"] convert_state();

      } else {

      }

    }

    state[ix,"t_last"] = t_cur;

    state[ix,"last"] = this;

  }

}

END {

  t_cur = $1/1.e9;

  for (ix=1; ix<=3; ++ix) {

    append_state();

    state[ix,"msg"] = state[ix,"msg"] convert_state();

  }

  for (ix=1; ix<=3; ++ix)

    print ix, state[ix,"msg"];

}