Object Files on Vax's Running Unix

Joel West joel at gould9.UUCP
Wed Nov 27 08:55:38 AEST 1985


In article <245 at uhpgvax.UUCP>, sandy at uhpgvax.UUCP (Sandy Phipps) writes:
> I would like some information or references that give
> 'detail' of the format for writing object files on vax's
> under the UNIX  BSD 4.2 operating environment.

I know this isn't what was asked for, but I'd agree, just use assembly
source output.  We tried to find out why all the existing compilers do 
it this way and came up with "just because".   I call this "THE CULT
OF THE MODULAR TOOLS."

However, it does make it a lot easier to debug, means you can write a 
very dumb one-pass code generator (you want dumb, look at cc -S with 
optimizing off) by letting the assembler resolve displacements, 
particularly all the the 127-bit displacement problems:

	jgeq	there		->	blss	ahead
					jmp	there
				ahead:

Also, as a side benefit, it's easy to write a compiler
that works under both VAX BSD and VAX System V.  The main
difference is that the System V doesn't support ".ascii"
directives. (yuk! :-()
-- 
	Joel West	 	(619) 457-9681
	CACI, Inc. Federal, 3344 N. Torrey Pines Ct., La Jolla, CA  92037
	{cbosgd,ihnp4,pyramid,sdcsvax,ucla-cs}!gould9!joel
	gould9!joel at nosc.ARPA



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