--- V9938.c.original	Tue Sep  7 06:57:28 1999
+++ V9938.c	Mon Apr 24 18:20:47 2000
@@ -166,6 +166,7 @@
   register int AX,AY,TX,TY,I,J,K;
   register int SX,SY,DX,DY,NX,NY,SM,TR;
   register byte *P,*T,CL;
+  register byte DCL;
 
   /* V9938 ops only work in SCREENs 5-8 */
   if(ScrMode<5) return(0);
@@ -223,7 +224,8 @@
   /* Compute point offset */
   I=Shift[SM][DX%PPB[SM]];
   /* Set the point */
-  *P=(*P&~(Mask[SM]<<I))|VDPOp(CL<<I,*P,Op&0x07);
+  DCL=(*P>>I)&Mask[SM];
+  *P=(*P&~(Mask[SM]<<I))|((VDPOp(CL,DCL,Op&0x07)&Mask[SM])<<I);
   /* Done with PSET */
   break;
 
@@ -285,7 +287,8 @@
     /* Set a point */
     P=VRAM+DY*BPL[SM]+DX/PPB[SM];
     I=Shift[SM][DX%PPB[SM]];
-    *P=(*P&~(Mask[SM]<<I))|VDPOp(CL<<I,*P,Op);
+    DCL=(*P>>I)&Mask[SM];
+    *P=(*P&~(Mask[SM]<<I))|((VDPOp(CL,DCL,Op)&Mask[SM])<<I);
     /* Done with LINE early */
     break;
   }
@@ -302,7 +305,8 @@
       /* Set a point */
       P=VRAM+DY*BPL[SM]+DX/PPB[SM];
       I=Shift[SM][DX%PPB[SM]];
-      *P=(*P&~(Mask[SM]<<I))|VDPOp(CL<<I,*P,Op);
+      DCL=(*P>>I)&Mask[SM];
+      *P=(*P&~(Mask[SM]<<I))|((VDPOp(CL,DCL,Op)&Mask[SM])<<I);
       /* Update counters */
       if(J>=0) { J-=AY;DX+=TX; }
     }
@@ -312,7 +316,8 @@
       /* Set a point */
       P=VRAM+DY*BPL[SM]+DX/PPB[SM];
       I=Shift[SM][DX%PPB[SM]];
-      *P=(*P&~(Mask[SM]<<I))|VDPOp(CL<<I,*P,Op);
+      DCL=(*P>>I)&Mask[SM];
+      *P=(*P&~(Mask[SM]<<I))|((VDPOp(CL,DCL,Op)&Mask[SM])<<I);
       /* Update counters */
       if(J>=0) { J-=AX;DY+=TY; }
     }
@@ -381,7 +386,8 @@
     {
       P=T+AX/PPB[SM];
       I=Shift[SM][AX%PPB[SM]];
-      *P=(*P&~(Mask[SM]<<I))|VDPOp(CL<<I,*P,Op);
+      DCL=(*P>>I)&Mask[SM];
+      *P=(*P&~(Mask[SM]<<I))|((VDPOp(CL,DCL,Op)&Mask[SM])<<I);
     }
    
   /* Done with FILL */
@@ -497,7 +503,8 @@
     {
       /* Get source point */
       AX=SX+J*TX;
-      CL=(T[AX/PPB[SM]]>>Shift[SM][AX%PPB[SM]])&Mask[SM];
+      I=Shift[SM][AX%PPB[SM]];
+      CL=(T[AX/PPB[SM]]>>I)&Mask[SM];
 
       /* If drawing this point... */
       if(CL||TR)
@@ -505,7 +512,8 @@
         AX=DX+J*TX;
         K=AX/PPB[SM];
         I=Shift[SM][AX%PPB[SM]];
-        P[K]=(P[K]&~(Mask[SM]<<I))|VDPOp(CL<<I,P[K],Op);
+        DCL=(P[K]>>I)&Mask[SM];
+        P[K]=(P[K]&~(Mask[SM]<<I))|((VDPOp(CL,DCL,Op)&Mask[SM])<<I);
       }
     }