Tcl之Lab1

Task 1.　　Use help

　1)　What is the default switch for the redirect command?　　-file

help -v redirect　　# or　redirect　-help

　2)　Use the very last example in the man page, can you use the -append switch when redirecting to a variable?　Yes.

man  redirect

　

Task 2.　　Count library cells

　　Count the number of muxes and xor gates available in the technology library core_slow.db. Given that:

　　- Library cells can be reported using the following command: report_lib core_slow.db

　　- All mux cells begin with the letters mx (eg mx2a1)

　　- All xor gates begin with the letters xor (eg xor3b15)

　1)　　First method

 # Redirect library report to a variable and use regexp
 redirect  -variable  rptstring  {report_lib  core_slow.db}

 regexp  -all  mx  $rptstring
 -> 36
 regexp  -all  cor  $rptstring
 -> 24

　2)　　Second method

 # Redirect the library report to a file and use the unix command grep
 # This is the less desirable method due to the potentially large memory
 # footprint required for the exec command
 redirect   tmp1212  {report_lib  core_slow.db}
 exec  grep  -c  mx  tmp1212
 -> 36
 exec  grep  -c  xor  tmp1212
 -> 24

 # Use grep without options to print each line containing a pattern
 exec  grep  xor  tmp1212
 # Delete the file if desired
 file delete tmp1212

Task 3.　　Analyze an unfamiliar script

 proc clock_domain {args} {

 # This Tcl procedure identifies the clocks constraining input ports
  foreach_in_collection each_port [get_ports -quiet $args] {

   set paths [get_timing_paths -from $each_port]
   foreach_in_collection each_path $paths {
      lappend port_array([get_object_name $each_port]) \
                    [get_object_name [get_attribute $each_path endpoint_clock]]
   }
  }

  foreach item [array names port_array] {
      echo "$item    $port_array($item)"
  }
 }

　1)　　How many commands are in this script?　　12 commands

　　　　Use the aquare brackets to help identify the embeddd commands.

　2)　　How many occurrences of variable substitution are there?　　8 occurrences

　　　　Use the $ to help identify the variable names. This procedure is using a type of variable called arrays.

　3)　　How many arguments are required for the proc command (recall that {} are used to identify a single argument)?

　　　　3 argumets. 　proc　clock_domain　{args}　{body}

　4)　　What symbol designates a comment in a script?　　#

　5)　　What symbol will continute a command over several lines?　　\