Index: r_segs.c
===================================================================
--- r_segs.c    (revision 4410)
+++ r_segs.c    (working copy)
@@ -365,7 +365,7 @@
           if (t + (int_64_t) textureheight[texnum] * spryscale < 0 ||
               t > (int_64_t) SCREENHEIGHT << FRACBITS*2)
             continue;        // skip if the texture is out of screen's range
-          sprtopscreen = (long)(t >> FRACBITS);
+          sprtopscreen = (int_64_t)(t >> FRACBITS);
         }

         dcvars.iscale = 0xffffffffu / (unsigned) spryscale;
Index: r_things.c
===================================================================
--- r_things.c  (revision 4410)
+++ r_things.c  (working copy)
@@ -441,7 +441,7 @@
 int   *mfloorclip;   // dropoff overflow
 int   *mceilingclip; // dropoff overflow
 fixed_t spryscale;
-fixed_t sprtopscreen;
+int_64_t sprtopscreen;

 void R_DrawMaskedColumn(
   const rpatch_t *patch,
@@ -453,8 +453,8 @@
 )
 {
   int     i;
-  int     topscreen;
-  int     bottomscreen;
+  int64_t     topscreen;
+  int64_t     bottomscreen;
   fixed_t basetexturemid = dcvars->texturemid;

   dcvars->texheight = patch->height; // killough 11/98
@@ -465,8 +465,8 @@
       topscreen = sprtopscreen + spryscale*post->topdelta;
       bottomscreen = topscreen + spryscale*post->length;

-      dcvars->yl = (topscreen+FRACUNIT-1)>>FRACBITS;
-      dcvars->yh = (bottomscreen-1)>>FRACBITS;
+      dcvars->yl = (int)((topscreen+FRACUNIT-1)>>FRACBITS);
+      dcvars->yh = (int)((bottomscreen-1)>>FRACBITS);

       if (dcvars->yh >= mfloorclip[dcvars->x])
         dcvars->yh = mfloorclip[dcvars->x]-1;