new config language.

[ron minnich]

I'm opening up this discussion, which was formerly just between the folks 
actively doing freebios2. We're getting closer to having things working 
and I am happy to hear any comments. 

linuxbios.a now builds for the K8 with the new config tool. Not all of 
linuxbios, just linuxbios.a, but that's quite a way to working.

Things are stricter now. We've been able to operate before with code like 
this:

#if SOME_VARIABLE_THAT_WAS_UNDEFINED == 0
	stuff
#endif

because in the GNU C preprocessor, 
#if (a == 0)
and
#ifndef a

are equivalent if a is undefined. 

I think that is a very poor way to operate: it can fool people, and in a 
BIOS you want more checking. 

Now that you can use an 'if' operator in the config language, setting up 
some things is a lot easier:

For example, this:
expr ROM_SECTION_SIZE  =(USE_FALLBACK_IMAGE*65536)+(USE_NORMAL_IMAGE*(ROM_SIZE 
- 65536))

expr ROM_SECTION_OFFSET=(USE_FALLBACK_IMAGE*(ROM_SIZE-65536))+(USE_NORMAL_IMAGE
*0)


now becomes this:
default FALLBACK_SIZE=65536
if USE_FALLBACK_IMAGE 
  option ROM_SECTION_SIZE  = FALLBACK_SIZE
  option ROM_SECTION_OFFSET= (ROM_SIZE - FALLBACK_SIZE)
end
if USE_NORMAL_IMAGE
  option ROM_SECTION_SIZE  = (ROM_SIZE - FALLBACK_SIZE)
  option ROM_SECTION_OFFSET= 0
end

Much better. However, if you have not defined USE_FALLBACK_IMAGE or 
USE_NORMAL_IMAGE, then you're going to get an error, which in the past was 
not the case. 

So we'll have to learn to be a bit more careful about defining things 
before they are used, and not using things that were never defined. This 
is all proving to be easy, but people will need to take more care with the 
Config files (which, in deference to Windows and MacOS, are now named 
Config.lb). 

ron