Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!isis!nlarson
From: nlarson@isis.cs.du.edu (Neil Larson)
Newsgroups: comp.lang.pascal
Subject: Re: Turbo 6.0: problem with inthtegrated debugger.
Message-ID: <1991Jan9.183514.7754@isis.cs.du.edu>
Date: 9 Jan 91 18:35:14 GMT
References: <2394@bnlux0.bnl.gov>
Reply-To: nlarson@isis.UUCP (Neil Larson)
Organization: Math/CS, University of Denver
Lines: 24

In article <2394@bnlux0.bnl.gov> kushmer@bnlux0.bnl.gov (christopher kushmerick) writes:
>I am having what appears to be recurring and intermittant problems
>with the integrated debugger. I am trying to use the F-4 (run to  cursor)
>command, and it reports that there is no code generated for this line.
>
>Sometimes it works correctly, sometimes not, for the same line.
>

Sometimes optimizations made by the compiler consist of using a similar line
of code near the one in question instead. Jeesh, this is hard to explain. 
say you have code that looks like this:


calculatecrc16(packet,crcval);
if crcval = 0 then
   crcvalerror := true;
calculatecrc16(packet,crcval);

the compiler will not create identical machine code for both calls to the 
procedure calls, but will just jump to the previous call. Stepping through the
code will show the current line executing and whats happening is obvious. You
can force the situation by inserting a writeln("put this line in"); at the 
point you want to stop. I learned this by tracking execution of turboc programs
with the debugger.