🚀 go-pugleaf

	Me and my finicky Pascal compiler can't get some code
to work. I'm trying to page flip and to do it, i want to copy 
everything from page 0 to page 1. Below is a hard-coded routine
to copy all of page 0 to page 1, hoping of course page 1
starts at 0a000:8000.
	And it don't work - it sometimes does nothing (page 1
stays the same) or else only icons with bit 0 set (like blue,
gray purple colors) are copied, but when they copy they make 
solid white icons. I assume somehow only bit 0 is being copied over,
which is why page 2 only has black and white images on it.
	I don't have the hang of switching planes, and since i 
have to copy from a plane from dest to plane on source, i hope
1 plane switch does tha plane switching for both source and dest.
If any of you have any ideas about what i could look at, please 
let me know.
	Kinda makes me wish i had an amiga...




Procedure Copy_Page; assembler;
(* Updates global variable Vis_Page                 *)
(* ES:DI - Destination (to)   DS:SI - Source (from) *)
(* CX    - Plane Loop         CX    - Row Loop      *)
 const
      ScreenWidth          = 320;
      ScreenHeight         = 200;

      Sequencer_Index      = $3C4;
      Color_Plane_Index    = $02;
      CurrentPlane : byte  = 8;

      Screen_Offset        = $0A000;
      ScreenBytes          = ScreenWidth div 8; (* Bytes per scanline *)
      PlaneBytes           = ScreenBytes*ScreenHeight;
      PlaneWords           = PlaneBytes div 2;
      Page_1_Offset        = ScreenBytes*ScreenHeight;
(* var
    CurrentPlane : byte;*)
  Asm
     push ds
     push es

     cld

     mov  CurrentPlane,8
     mov  cx,4   (* Num Planes *)

     mov ax,Screen_Offset
     mov ds,ax

     mov ax,Screen_Offset
     mov es,ax

 @@Set_Address:
     mov di,Page_1_Offset
     xor si,si

     @@Plane_Loop:
         push cx           (* Save Plane Number *)

         mov dx,Sequencer_Index    (* set plane *)
         mov al,Color_Plane_Index
         out dx,al
         inc dx
         mov al,CurrentPlane
         out dx,al

         mov cx,PlaneWords  (* copy that plane *)
         rep movsw

         shr CurrentPlane,1    (* next plane *)
         pop cx                (* set cx back to planes *)

         loop @@Set_Address

     pop es
     pop ds
  End;