Date   : Sat, 09 Sep 2006 10:49:12 +0100
From   : Sprow <info@...>
Subject: Re: Bugs in ArmCoPro OS

In article <060909095504@...>,
   Jonathan Graham Harston <jgh@...> wrote:
> >Message-ID: <4e624f8069info@...>
>  
> Also, the ARMCoPro OS doesn't pass A back on calls to OSGBPB. A
> Tube Client OS should pass back A unchanged. OSGBPB returns A=&00
> if call supported, or A=unchanged if call unsupported. [SJ MDFS
> Manager's Guide, p10-2]

This is intentional - it's implementing the SWI OS_GBPB which is defined as
preserving R0, not CALL &FFD1 which for my money returns A undefined at
worst (page 342 Advanced user guide) or A preserved (page H3-3 Master
reference manual) at best.

The ARM Tube OS implements 343 SWIs, and as a general rule the return
results are per the SWI documentation (E&OE!) unless otherwise noted in
 http://www.sprow.co.uk/bbc/hardware/armcopro/armtubeoscalls.pdf
as behaving differently in some way,
Sprow.