#4 Patch to the "missing label before goto $-1" problem

[Joaquín Ferrero]

(Summarize: change 308 line to solve the "missing label before goto $-1" problem)

In this case:

    clrf            mem_30, f   ; 0010: 01B0
    clrf            mem_0c, f   ; 0011: 018C
                                ;              <=== NO label_0012 !!!
; jump here from: 0032
    btfss           mem_05, 3   ; 0012: 1D85
    goto            $-1         ; 0013: 2812   <=== guilty

    call            sub_04b     ; 0014: 204B
; [...]
    goto                        ; 0032: 2812   <=== NO label_0012 !!!

The problem is with the goto $-1. The program run this ($pc = 0x0013):

523:                elsif ($pc-1 == $addr) {
524:                    undef $prog{$addr}{label};
525:                    delete $prog{$pc}{addr};
526:                    $prog{$pc}{arg} = '$-1';
527:                }

In this moment, $prog{0x0012}{label} is created with a 'undef' value.

More later, when display() run:

948:        # display label if any
949:        if ( (exists $prog{$pc}{jumpref})
950:        or   (exists $prog{$pc}{label}) )
951:        {
952:            $label = getLabel($pc);

Of course, {jumpref} exists (jump to 0012), and {label} (created by goto in 0013), but at line 952, it call to getLabel():

305:    my $lbl = sprintf("label_%03x", $pc);
306:
307:    # oh, we have a better name for this address
308:    if (exists $prog{$pc}{label}) {
309:        $lbl = $prog{$pc}{label};
310:    }

the problem now is that $prog{$pc}{label} exists, but with a 'undef' value, so $lbl will by 'undef', so a void label will be show (not visible).

Solution: modify line 308:

308:    if ($prog{$pc}{label}) {