[B2-devel] PATCH: new file lowmem.c

[Michael S. <msl...@co...>]

Hi all,

I have b2 running in real addressing mode with video on segv under X in 
Darwin. The changes are not trivial so I will send them out in parts 
with explanation to make feed back easier. There are two main additions 
conceptually.

A mechanism to enable mapping the low memory globals:
I wrote a utility to modify the __PAGEZERO segment of the executable to 
allow this.

A mechanism to enable faulting on video buffer accesses:
I added code to use the extended mach exception present in Darwin.

Also there were other changes that I added along the way, mainly to 
support both X/Aqua builds to work.

I am still writing the necessary autoconf tests and reviewing some of 
the changes.

I have attached lowmem.c which is the source to the utility which 
enables low memory global access. It is intended for it to live in 
src/Unix/Darwin and it will be built and used during the 
configure/build process.

As a note, the Aqua port under src/MacOSX updates the entire view each 
time it is updated. Some more changes than what I have ready would need 
to be added to get that to work with VOSF so that only the areas in 
need of updating are actually redrawn. (I am referring to 
setNeedsDisplay in Emulator.mm, this needs to be changed to 
setNeedsDisplayInRect with code analogous to that in the UNIX version 
that determines which areas are in need up updating.)

mzs