ModelSim SE User's Manual - Electrical and Computer Engineering

UM-478 20 - Tcl and macros (DO files)
Command separator
Multiple-line commands
Evaluation order
ModelSim SE User’s Manual
A semicolon character (;) works as a separator for multiple commands on the same line. It
is not required at the end of a line in a command sequence.
With Tcl, multiple-line commands can be used within macros and on the command line.
The command line prompt will change (as in a C shell) until the multiple-line command is
complete.
In the example below, note the way the opening brace ’{’ is at the end of the if and else
lines. This is important because otherwise the Tcl scanner won't know that there is more
coming in the command and will try to execute what it has up to that point, which won't be
what you intend.
if { [exa sig_a] == "0011ZZ"} {
echo "Signal value matches"
do macro_1.do
} else {
echo "Signal value fails"
do macro_2.do
}
An important thing to remember when using Tcl is that anything put in curly brackets {} is
not evaluated immediately. This is important for if-then-else statements, procedures, loops,
and so forth.
Tcl relational expression evaluation
When you are comparing values, the following hints may be useful:
Tcl stores all values as strings, and will convert certain strings to numeric values when
appropriate. If you want a literal to be treated as a numeric value, don't quote it.
if {[exa var_1] == 345}...
The following will also work:
if {[exa var_1] == "345"}...
However, if a literal cannot be represented as a number, you must quote it, or Tcl will
give you an error. For instance:
if {[exa var_2] == 001Z}...
will give an error.
if {[exa var_2] == "001Z"}...
will work okay.
Don't quote single characters in single quotes:
if {[exa var_3] == 'X'}...
will give an error
if {[exa var_3] == "X"}...
will work okay.