[Tack-devel] ack.out vs. ELF

[David G. <dg...@co...>]

I've been reading the discussion of file formats with a certain amount of=

interest, but I suspect people are reading more into it than there actual=
ly is...

It's worth remembering that the ACK isn't just a toolchain, it's a *platf=
orm*.
The em specification dictates a certain (flexible) program layout; there'=
s
even an interpreter that implements the VM. An em program communicates wi=
th
the outside world via system calls (the MON em opcode; the model is very
similar to the way V7 Unix worked, even down to the syscall numbering). T=
he
ACK comes with its own portable libc that uses these syscalls to do all t=
he
work; I suspect a lot of the build confusion comes from mistaking headers=

intended to be used by programs compiled *by* the ACK with headers used b=
y the
ACK itself.

As a result of this, the ACK knows absolutely nothing about shared librar=
ies.

However, there's no reason why we have to use the ACK's platform. It's
perfectly possible to compile a program referring to headers in /usr/incl=
ude,
link it with led into a partially linked object file (because led can't l=
ink
to shared libraries, of course), exporting it to ELF (using a program yet=
 to
be written), and then linking the result to shared libraries using the
platform linker.

If you do this then you'll lose the portability across platforms that the=
 ACK
was originally aiming for, but frankly, that's not particularly important=

these days.

I am planning to write two ack.out converters at some point, one for ELF =
and
one for a simple binary image; however, I don't know a lot about ELF and =
so
this would require a lot of reading up on... it may be easier instead to
persuade someone who knows about such things to add ack.out support to th=
e GNU
binutils toolchain instead, so that ld can read them in directly. ack.out=

doesn't look very complicated.

--=20
+- David Given --McQ-+ "Gaping from its single obling socket was
|  dg...@co...    | scintillating, many fauceted scarlet emerald..."
| (dg...@ta...) | --- Jim Theis, _The Eye of Argon_ (spelling
+- www.cowlark.com --+ original)