[OpenBIOS] ASM/C and 16/32 bit questions.

[David Woodhouse]

dcinege at fuckthejunkmailers.org said:
>  When I think 32-bit in the BIOS, to me that means being able to deal
> with larger drives, and booting partitions with a huge sector offset.
> (corrections please)

Thank God for that - I was getting worried there! We want that kind of
functionality, definitely. 


When I think 32-bit, that means "protected mode" - 32-bit code and data, rather
than the old real mode 16-bit segment/offset methods.

This would have meant that it wouldn't be compatible with legacy operating
systems such as DOS and Windows 95 which run at least partly in real mode,
using the real mode interrupts into the BIOS. (Unless we provided such 16-bit
routines side-by-side with the 32-bit ones, effectively doubling the size of
our function code)

We can provide big drive support and other such niceties with real mode code -
a normal BIOS generally has very little protected mode code AFAIK, although it
is required to provide routines for copying data to/from high memory, and for
switching into protected mode.






----                              ----                              ----
David Woodhouse, Robinson College, CB3 9AN, England.   (+44) 0976 658355
    Dave at imladris.demon.co.uk        http://dwmw2.robinson.cam.ac.uk
	    finger pgp at dwmw2.robinson.cam.ac.uk for PGP key.



---
OpenBIOS -- http://www.linkscape.net/openbios/
openbios-request at linkscape.net   Body: un/subscribe
Problems?  dcinege at psychosis.com