[OpenBIOS] SOLVED: the mystery of Solaris on SPARC32 and the missing Forth arguments

Mark Cave-Ayland mark.cave-ayland at siriusit.co.uk
Fri Oct 22 20:45:55 CEST 2010

Blue Swirl wrote:

>> Ah okay - so swap retl with plain ret? And can I just use %sp like the
>> SPARC64 version?
> Yes. If you add 'save' and 'restore', then %sp can be used.

Okay - perhaps I'm missing something more fundamental here. The attached 
patch creates a simple handler that does nothing except flush windows to 
the stack and then call the C function - but it still seems to corrupt 
the stack somehow as subsequent calls into OBP have the wrong parameters.

The only thing I can think of is that this simple example fails because 
of something related to the return address, but I'm not 100% sure. Also 
what are the rules about how much information you can push onto the 
stack of the previous frame, i.e. the frame pointer? My current thoughts 
are that I can either i) push arguments onto the %fp and not save into a 
new window or ii) push arguments onto the %sp after a save (in which 
case I need additional code to copy the i registers into the o registers 
before calling the C function). Does this sound correct?



Mark Cave-Ayland - Senior Technical Architect
PostgreSQL - PostGIS
Sirius Corporation plc - control through freedom
t: +44 870 608 0063

Sirius Labs: http://www.siriusit.co.uk/labs
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