[AD] quad3d(POLYTYPE_PTEX_LIT) crashes with watcom

[Sven Sandberg <svsa1977@xxxxxxxxxx>]

ex3d crashes for me under mysterious circumstances with 4.0.0 (release)
and Watcom 10.6. I'm running from a dos box under windows 95 on a
Pentium 133 (i.e. no fancy mmx or sse). It doesn't seem to happen under
djgpp.

It crashes when you select POLYTYPE_PTEX_LIT, and then run it some time
(usually about 15 sec - 2 min, I think). I also managed to find a
specific call to quad3d() that crashes reproducably (see the program
below). However, this program gives a slightly different result: it
locks up after it has printed "Shutting down Allegro\n", i.e. before the
actual traceback.

Any ideas?

-------- begin traceback --------
Shutting down Allegro
DOS/4GW error (2001): exception 0Eh (page fault) at 237:82F3A687
TSF32: prev_tsf32 5278
SS       23F DS       23F ES       23F FS         0 GS        87
EAX F000EF6F EBX     10F3 ECX      F00 EDX        0
ESI 826404C4 EDI 832142C4 EBP 8327F578 ESP 8327F160
CS:IP  237:82F3A687 ID 0E COD        4 FLG   210282
CS=  237, USE32, page granular, limit FFFFFFFF, base        0, acc CFFB
SS=  23F, USE32, page granular, limit FFFFFFFF, base        0, acc CFF3
DS=  23F, USE32, page granular, limit FFFFFFFF, base        0, acc CFF3
ES=  23F, USE32, page granular, limit FFFFFFFF, base        0, acc CFF3
FS=    0, USE16, byte granular, limit        0, base        0, acc  0
GS=   87, USE16, byte granular, limit     FFFF, base    1ED50, acc F3
CR0: unavailable
Crash address (unrelocated) = 1:00003687
-------- end traceback --------

-------- begin crash.c --------
#include <allegro.h>
COLOR_MAP light_table;

int main(int argc, char *argv[])
{
   V3D vtx1, vtx2, vtx3, vtx4;
   BITMAP *bmp, *texture;

   allegro_init();
   set_gfx_mode(GFX_AUTODETECT, 320, 200, 0, 0);
   create_light_table(&light_table, desktop_palette, 0, 0, 0, NULL);
   color_map = &light_table;

   bmp = create_bitmap(320, 200);
   clear(bmp);
   texture = create_bitmap(32, 32);
   clear_to_color(texture, 255);

   vtx1.x=11726240; vtx1.y=7579000; vtx1.z=61833760;
   vtx1.u=0;        vtx1.v=0;       vtx1.c=19;
   vtx2.x=12037280; vtx2.y=7223700; vtx2.z=63607072;
   vtx2.u=2097152;  vtx2.v=0;       vtx2.c=13;
   vtx3.x=11911200; vtx3.y=7372800; vtx3.z=67331232;
   vtx3.u=2097152;  vtx3.v=2097152; vtx3.c=0;
   vtx4.x=11614400; vtx4.y=7711900; vtx4.z=65557920;
   vtx4.u=0;        vtx4.v=2097152; vtx4.c=5;

   quad3d(bmp, POLYTYPE_PTEX_LIT, texture, &vtx1, &vtx2, &vtx3, &vtx4);

   return 0;
}
END_OF_MAIN()
-------- end crash.c --------

-- 
Sven Sandberg    svsa1977@xxxxxxxxxx    home.student.uu.se/svsa1977