Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!unmvax!pprg.unm.edu!hc!lll-winken!uunet!vuwcomp!andrew
From: andrew@comp.vuw.ac.nz (Andrew Vignaux)
Newsgroups: comp.sys.hp
Subject: 9000/835 loader and assembler problems
Message-ID: <14870@comp.vuw.ac.nz>
Date: 1 Jun 89 04:20:46 GMT
Reply-To: andrew@comp.vuw.ac.nz (Andrew Vignaux)
Organization: Comp Sci, Victoria University, Wellington, New Zealand.
Lines: 62
X-Running: HP9000/835, HPUX 3.01

I've hit a small problem trying to port KCl to our 835.

KCl uses dynamic loading [ld -A] to load its object files into
memory.  However, it has appended some text to the object file which
it loads separately.  All the lds that I have seen before, allow extra
rubbish on the end of object files, but the 835 loader says

	/bin/ld: foo.o: Not a valid object file (invalid system id)

if the length of the data is >= 128 bytes.  Interestingly, it works
fine if the length is < 128 bytes.  [The system-id is valid in both
cases!]  Any ideas?

Another problem I am having, is what to do with the object file after
I have loaded it.  I read the object module's header to determine how
much space I should allocate in memory.  I allocate the space, and
pass the starting address to "ld -A bar -R %x -o baz".  The object file
that I get back has a number of interesting properties

  - the starting address of the text segment has been rounded up to a
    page boundary -- is there anything in the architecture that
    requires this?

  - the starting address of the data segment has also been rounded up
    to a page boundary.  Again is there any real reason for this?

  - I want to branch to the first routine in the file.  The
    inter-space stub seems to be at TEXT+4 (*TEXT is a break).  Is
    there a better way to find this?

  - the header gives a different size than the one I worked out
    earlier [Surprise, surprise].  Any suggestions on a better size
    predictor (I am currently using size+PAGESIZE).

I guess I should write my own linker :-(

While I've got your attention :-), are there any 9000/800 assembler
gurus out there?

I've got the following declaration C declaration:

	extern struct character character_table[];

which KCl indexes with a character.  Because characters are signed on
some machines, the space for the array is defined in an assembler file

		.globl	_character_table
		.space	1024
	_character_table:
		.space	1024

in the appropriate syntax for the particular machine.  Note: the label is in
the middle of the space.  I've been able to put this in the DATA
subspace but not in the BSS subspace.  Any thoughts on how to get this in
the BSS subspace?

Is it possible to get the assembler to define a symbol that is the
value of another symbol + an offset?

Andrew
-- 
Domain address: andrew@comp.vuw.ac.nz   Path address: ...!uunet!vuwcomp!andrew