Re: New GNAT ports (was Re: Ada and Automotive Industry)

[dewar@merv.cs.nyu.edu (Robert Dewar)]

Robert Eachus says

"   For the 8051, starting with an the a version of gcc for the Intel
8086, 80186, 80286, or even the Z-80 should be a good start.  But a
gcc version that targets are 386 or higher is probably a waste of
effort as a starting point."


This is a little confused. There is only one version of GCC, which is
common across all targets. What specializes GCC to a particular target
is the machine description file, which is essentially a formal description
of the semantics of the target architecture. I don't see that the 
MD file for the 8086 would be a particularly helpful starting point for
the 8051, except perhaps as a general indication of how MD files are
written, although if you are not already thoroughly familiar with the
mechanics of writing MD files for GCC, then you would be unlikely to
succeed anyway with the 8051, which as has often been discussed here,
is not an easy machine to target.

Now it is also the case that if you tried to do an efficient GCC port
to the 8051, you might well need to make some improvements in GCC, that's
a steady process, and often driven by requirements that are initially
generated by targetting to new architectures. The general idea here is
not to put in special kludges for particular architectures (there is almost
no specialization of this kind in GCC), but rather to abstract the general
features involved, and provide enhancements that will be useful to any
targets sharing the particular features involved.

So it is quite likely that the 8051 might suggest some general improvements
of this type, but there again, I doubt the 8086 would be a useful comparison
point.