A TLC Tutorial (Target Language Compiler)

Target Language Compiler

Debug gain.tlc

Now let's look around to find out what is wrong with our code:

Set a breakpoint on line 49 of gain.tlc:

```
TLC-DEBUG> break gain.tlc:49
```

Instruct the TLC debugger to advance to your breakpoint:

```
TLC-DEBUG> continue
```

TLC processes input, reports its progress, advances to line 50 in gain.tlc, displays the line, and pauses:

### Loading TMW TLC function libraries
..
### Initial pass through model to cache user defined code
### Caching model source code
Warning:  USING LOCAL VERSION OF gain.tlc 
.
Breakpoint 1
00049:     %if InlineParameters == 1

Use the whos command to see the variables in the current scope:

TLC-DEBUG> whos
Variables within: <BLOCK_LOCAL>
k                              String
rollVars                       Vector
u                              String
y                              String
block                          Resolved
system                         Resolved

Inspect the variables using the print command (note, names are case sensitive):

TLC-DEBUG> print k
1.0

TLC-DEBUG> print rollVars
[U, Y, P]

TLC-DEBUG> print u
u0[i1]

TLC-DEBUG> print y
y0[i1]

Execute one step:

TLC-DEBUG> step
00051:       %<FcnEliminateUnnecessaryParams(y, u, k)>\

(We reached this statement because InlineParameters is TRUE.)

Step again, into FcnEliminateUnnecessaryParams:

TLC-DEBUG> step
00024: %if LibIsEqual(k, "0.0")

Rather than stepping into LibIsEqual(), advance via the next command:

TLC-DEBUG> next
00028:   %elseif LibIsEqual(k, "1.0")

Examine k's value:
- ```
TLC-DEBUG> print k
1.0
```

Since k does equal 1.0, the statement following the %if is executed:

TLC-DEBUG> next
00029:     %<y> = %<k>;

Examine y's value:
- ```
TLC-DEBUG> print y
y0[i1]
```

Advance once more time and you'll see that this function is finished:

TLC-DEBUG> next
00051:       %<FcnEliminateUnnecessaryParams(y, u, k)>\

Clearly, this is the origin of the C statement responsible for the erroneous constant output, rtb_first_output = 1.0;.

Abandon the build by quitting the TLC. Type

```
TLC-DEBUG> quit
```

Start the Debugger and Explore Commands Fix the Bug and Verify the Fix