Initial register contents

Simon Willcocks

unread,

Dec 30, 2009, 7:34:51 AM12/30/09

to

Hi,

I'm looking at running absolute RISC OS executables (under emulation) on
ROLF, and I need to know what an application should be able to expect in the
registers on startup. I'll try to work it out myself, and maybe search
through the manuals some more, but if someone can point me to the right
information it would save me some time.

The RO3 PRM explains the register contents for transient programs (page
1-285) and the various module entry points (which I seem to have working),
but not "normal" applications run at &8000. Have I missed something?

TIA,
Simon

--
ROLF - The RISC OS Look and Feel on Linux.
http://stoppers.drobe.co.uk
http://ro-lookandfeel.blogspot.com/

Martin Wuerthner

unread,

Dec 30, 2009, 9:35:26 AM12/30/09

to

In message <e5e5c1d150.s...@home.invalid>
Simon Willcocks <simon.w...@t-online.de> wrote:

> I'm looking at running absolute RISC OS executables (under emulation) on
> ROLF, and I need to know what an application should be able to expect in the
> registers on startup. I'll try to work it out myself, and maybe search
> through the manuals some more, but if someone can point me to the right
> information it would save me some time.

> The RO3 PRM explains the register contents for transient programs (page
> 1-285) and the various module entry points (which I seem to have working),
> but not "normal" applications run at &8000. Have I missed something?

The information can be found on the previous page but you may not have
realized that this is the complete specification: Applications are
entered in USR mode with interrupts enabled. If the application is a
module task R12 contains the usual private word pointer.

That is all there is to it. The implication is that all registers are
undefined (apart from R12 in case of a module task).

Martin
--
---------------------------------------------------------------------
Martin Wuerthner MW Software http://www.mw-software.com/
ArtWorks 2 -- Designing stunning graphics has never been easier
spam...@mw-software.com [replace "spamtrap" by "info" to reply]

Simon Willcocks

unread,

Dec 30, 2009, 11:45:33 AM12/30/09

to

In message <24f0ccd1...@bach.planiverse.com>
Martin Wuerthner <spam...@mw-software.com> wrote:

> In message <e5e5c1d150.s...@home.invalid>
> Simon Willcocks <simon.w...@t-online.de> wrote:
>
> > I need to know what an application should be able to expect in the
> > registers on startup.
>

> > The RO3 PRM explains the register contents for transient programs (page
> > 1-285) and the various module entry points (which I seem to have working),
> > but not "normal" applications run at &8000. Have I missed something?
>
> The information can be found on the previous page but you may not have
> realized that this is the complete specification: Applications are
> entered in USR mode with interrupts enabled. If the application is a
> module task R12 contains the usual private word pointer.
>
> That is all there is to it. The implication is that all registers are
> undefined (apart from R12 in case of a module task).

Thanks Martin, that should be fairly easy to implement!