🚀 go-pugleaf

To do my thesis work, I have been using Aztec C compiler on a Speary IT
computer equipped with an IBM EGA (256K ega ver).  Since the compiler 
does not know what the ega is, I had to write (copy from books) some 
routines that seem to display my images correctly.  

The problem seems to come when I compile my programs with the (+F) option
on the compiler.  This option supposedly creates Fast code.  When I
compile my routines with the +F, my program runs, but my images are
displayed in a strange repeating pattern on the screen.  When I omit the
+F, my program works perfectly. 

I know, you're going to say "Well, don't use the +F option", but can there
be some REAL reason for this to happen?  

One additional note, I am compiling my programs using the large code+large
data options.

Thanks for any insight.

mwg