[SeaBIOS] SeaBIOS 16-bit compiler

[Kevin O'Connor]

Hi Michal,

I'm CC'ing the SeaBIOS mailing list.

On Thu, Mar 25, 2010 at 06:32:50AM -0700, Michal Necasek wrote:
> Have you ever looked into the possibility of using a real 16-bit
> compiler for the 16-bit bits? One obvious candidate would be Open
> Watcom C/C++. Microsoft Visual C++ 1.52 is also a very capable
> 16-bit compiler, but probably not a real option for SeaBIOS due to
> limited availability and host platform support.

This has come up a couple of times in the past.

One thing to note is that SeaBIOS actually has more 32bit code than it
does 16bit code.  Also, large portions of the code are compiled in
both modes.

I hear Open Watcom works well for 16bit code, but I'd guess gcc does a
better job with regular 32bit code.  A solution for the 16bit code
wouldn't work well if it reduced the code sharing with the 32bit code.
Either all the code would need to be compiled with Open Watcom or the
final SeaBIOS binary would need to be a mix of gcc and Open Watcom
code - both seem risky.

The other difficulty with Open Watcom is its availability.  It's nice
to be able to compile SeaBIOS without requiring special packages.
That was a big advantage for the qemu/kvm maintainers.

-Kevin