[OpenBIOS] PATCH v2: Rework CIF interface to handle parameters in reverse order

[Mark Cave-Ayland]

Nick Couchman wrote:

> (Sorry if the patch wasn't supposed to fix this...)
> 
> After applying this patch still getting:
> 
> OpenBIOS for Sparc64
> Configuration device id QEMU version 1 machine id 0
> CPUs: 1 x SUNW,UltraSPARC-II
> UUID: 00000000-0000-0000-0000-000000000000
> claim isn't unique.
> release isn't unique.
> Welcome to OpenBIOS v1.0 built on Nov 30 2009 15:44
>   Type 'help' for detailed information
> 
> 0 > boot cdrom 
> [sparc64] Booting file 'cdrom' with parameters ''
> Not a bootable ELF image
> Not a Linux kernel image
> Not a bootable a.out image
> Loading FCode image...
> Loaded 7120 bytes
> entry point is 0x4000
> Evaluating FCode...
> Unhandled Exception 0x0000000008000000
> PC = 0x00000000ffd10e3c NPC = 0x00000000ffd10e40
> Stopping execution
> 
> 
> and GDB shows the error at:
> (gdb) l *0x00000000ffd10e3c
> 0xffd10e3c is in cfetch (../include/openbios/stack.h:34).
> 29	typedef ucell phandle_t;
> 30	
> 31	
> 32	
> 33	
> 34	static inline void PUSH(ucell value) {
> 35		dstack[++dstackcnt] = (value);
> 36	}
> 37	static inline void PUSH_xt( xt_t xt ) { PUSH( (ucell)xt ); }
> 38	static inline void PUSH_ih( ihandle_t ih ) { PUSH( (ucell)ih ); }
> 
> Let me know if I can provide any additional output or debugging steps!
> -Nick

Well, it got things a bit further but there is still another bug 
present. In this case the backtrace is useless because it's a Forth 
issue rather than a C issue - it's often more useful to step through in 
Forth first to see which word causes the breakage rather than post a 
backtrace from within the Forth engine.

In this case, I did a little bit of detective work and found that the 
branch offset calculations are wrong for certain combinations of nested 
b(<mark) and bbranch. I'm fairly sure I can fix this, I just need to 
find a moment to come up with a fix and test it. Oh, and I'll apply the 
above patch too.


ATB,

Mark.

-- 
Mark Cave-Ayland - Senior Technical Architect
PostgreSQL - PostGIS
Sirius Corporation plc - control through freedom
http://www.siriusit.co.uk
t: +44 870 608 0063

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