On Tue, May 07, 2002 at 12:17:46AM +1000, Luke Mewburn wrote:

 > 	+ Should bootxx always contain the 32 byte PROM magic prepended
 > 	  to the start?  If not, I'll instead add an installboot -o
 > 	  option for the sparc backend to control this. 

The "32 bytes of PROM magic" is actually a very cleverly crafted a.out
header (I think Solaris called it something else, but an a.out header
is actually what it is :-) .. the a_midmag field contains a magic number
that just so happens to be a jump of exactly the right size to leap over
the a.out header to the real code.

It is this way because some PROM versions expected a flat binary bootxx,
and some expected an a.out bootxx, and we have a bootxx that works with
both.

Anyway, there is some context for you.

 > An alternate option would be to convert the primary boostrap bootxx
 > away from the bbinfo approach (of hard-coded blocks) to a "search
 > the filesystem for /boot" approach a la the alpha/pmax/vax/sparc64.
 > This is much more effort, but would result in one less "bootxx flag
 > day".

I'm not sure there's room in the SPARC bootxx to do this.

-- 
        -- Jason R. Thorpe <thorpej@wasabisystems.com>