🚀 go-pugleaf

In article <1992Aug17.234228.16195@leland.Stanford.EDU> buc@leland.stanford.edu (Robert Richards) writes:
>
>I am trying to port a C program to the Cray under UNICOS.  The slowest
>part of the port is the 32-bit references that I have to convert to
>CRAY's 64-bit world.  Are there any tools that help one find where
>code is not 64-bit world compatible?

I've lost count of how many codes I've ported to the Cray.  It's not always
hard, but then people are always doing things to screw you up.  I don't know
of any specific tools, but I usually run a lot of greps.

First step, get the code to compile and run correctly with an ANSI C compiler
on a 32 bit machine (or wherever the code is known to work correctly.)
Most 64 bit portability problems won't be caught by the compiler but you
really should start with a clean program.

Step two, look for all references (grep) to read and/or write.  Quite often
this indicates that the program is doing binary IO...there is nothing wrong
with this but it can indicate a problem with moving files to other machines.
Redefine all binary IO in terms of a stream of bytes.

Look for unions (this one just got me).....these could be indications of 
somebody trying to mess with the bits (overlaying a float and an integer,
for example.)  Since you are doing ME and not EE I suspect you won't  see
too much bit twiddling, either.

Finally, run the program and see where it stops.  

It's really not hard to write portable 64/32 bit code.....keep your fingers
crossed.  Going the other way is even harder.

							Malcolm Slaney
							Apple ATG