Re: [9fans] Linuxemu

["Russ Cox" <rsc@plan9.bell-labs.com>]

> thanks a lot for linuxemu! However, I was only able to run the stuff
> included with /bin. Other linux progs (sort, bc...) did not work
> (see below). May it be they were dynamically linked with glibc?
> Thus, isn't there a dosemu around there? (Perhaps it would be easier

right, /bin is typically statically linked, while /usr/bin
is dynamically linked.  like i said, it wouldn't be too hard
to make dynamic linking work.  in theory,

	linuxemu ld-linux.so.1 bin/a.dynamic

is supposed to work, but unfortunately ld-linux.so.1
wants to be loaded where the linuxemu text segment is.
you'd need to move the linuxemu text segment somewhere
else and then segdetach it before calling elfload.  it's entirely
doable, especially since x86 code is position independent.

dosemu is much harder because you have to deal with
all the weird 16-bit processor modes.  at that point it's easier
just to simulate the 16-bit processor than to get plan 9 to
set up the processor the way you want it.  the other problem
with dosemu is that the set of system calls doesn't map as
nicely to plan 9 system calls.  i wrote one of those too, but
only enough to execute the vga bios code.  the theory was
that this might be significantly easier than the kernel support
required.  i still think that's true, but it didn't just work.  there
are some things that need certain timing to work out properly,
and the simulator is too slow.  at least, that's my theory.
i think there's still hope for it -- you could hard code certain
sequences that had to run nearer to full speed and run them
as one pseudo-op in the simulator.