It's not syscall calling convention, and CSet/2 generates thunks that call
this function but expect %ecx to not be altered by it. Save off a bunch,
just in case.
- Let allocateSelector() specify number of pages to allocate.
- Let findSelector() specify if this is a code or data segment.
- Let findSelector() choose if this is a code or data segment
if the caller doesn't know (DosFlatToSel(), etc).
Now we save off the stack pointer and immediately jmp back to 32-bit. This is
slightly easier to debug (gdb doesn't get confused by addresses, registers or
disassembly), and puts all the 32-bit registers in a 32-bit code segment, to
keep things sane.
Also: doesn't write duplicate instructions to update %ds and %es if they are
the same values in Linux land.
Finger (etc) also rely on MPTN\DLL\tnls32.dll, which I pulled out a copy of
OS/2 Warp 4.52, which loads and limps along enough to not be a problem.
Reimplementing that library is going to be a pain, so that's a job for another
day. Inexplicably, tnls32 references pmgpi.dll's GpiQueryTextBox(), so I put a
stub for that in, too, but we're nowhere near really implementing GPI yet.
This is enough to run "finger.exe icculus@icculus.org" and see my .plan file,
which I consider a victory. A few more TCP/IP command line tools aren't far
behind.
This gets us everything we need (I hope!) to support 16-bit code in LX
binaries and call into 16-bit OS/2 APIs. This is just enough to call
into VioGetMode() (which isn't otherwise implemented yet) as an example.
If this is ever used Winelib-style to provide an OS/2 API to native Linux
binaries, the 16-bit system APIs are 32-bit clean and C callable, as one
might expect them to be. All the tapdancing is to support existing LX
binaries in the loader and bridge between the 32-bit clean APIs and
existing 16-bit code that expects to call 16-bit APIs.
This was a staggering amount of effort, but yay!
Other fixes and improvements probably leaked into this commit, as a
lot of code got touched and a lot of research and debugging took place.
Otherwise, it won't be available to DLL init code when run before the
main executable starts.
Fixes Watcom C's wlink.exe crashing because it gets a NULL command line.
I must have been reading docs for device drivers, or something...?
Now it returns the top word of the linear pointer, in hopes that this will
just get mushed back together later, knock on wood.
This is enough to survive emx.dll intialization and a printf("hello world")
mainline, but note that we need to properly implement DosQueryHType()
before EMX's printf() will work, though (as it currently thinks stdout isn't
open), so we're not quite through a proper C Hello World test yet.
Wanted to do this now before it gets out of hand.
Ideally, this can be used for a Winelib-like option eventually, too, where you
don't load OS/2 binaries at all but rather compile and link your OS/2-based
source code against this API reimplementation.
It looks like most of the remaining work for that is filling in dozens of
OS/2 APIs that EMX uses at startup just so we can get to our single
printf() call. :)
Ryan C. Gordon