Initial. Don't... just don't ask.

demos/rwpage.pp

@@ -0,0 +1,83 @@
+PROGRAM ScrollTest;
+
+Uses svgalib;
+
+type
+  VideoMemType = array[0..65535] of byte;
+
+var
+  i,mode,StartupMode	   : longint;
+  SeparateReadWriteWindows : boolean;
+  modeinfo		   : ^vga_modeinfo;
+  VideoMem		   : ^VideoMemType;
+  p : pointer;
+
+
+Procedure DrawRectangle(x1,y1,x2,y2 : integer);
+begin
+  vga_drawline(x1,y1,x2,y1);
+  vga_drawline(x1,y2,x2,y2);
+  vga_drawline(x1,y1,x1,y2);
+  vga_drawline(x2,y1,x2,y2);
+end;  {DrawRectangle}
+
+
+Procedure Scroll;
+{ copies first bank of screen to the last bank (for 1024x768x256 mode) }
+var  i : word;
+begin
+  vga_setreadpage(0);
+  vga_setwritepage(11);
+  for i := 65535 downto 0 do VideoMem^[i] := VideoMem^[i];
+end;  {Scroll}
+(*  
+Procedure Scroll;  Assembler;
+{ copies first bank of screen to the last bank (for 1024x768x256 mode) }
+var  popreturn : longint;
+asm
+       mov   esi,SegA000
+       mov   edi,esi
+       mov   eax,0
+       push  eax
+       call  vga_setreadpage  {set read bank}
+       pop   popreturn        {tidy stack}
+       mov   eax,11
+       push  eax
+       call  vga_setwritepage {set write bank}
+       pop   popreturn        {tidy stack}
+       mov   ecx,16384
+       rep   movsd            {copy all of bank 0 to bank 11}
+end;  {Scroll}
+*)
+
+begin
+  mode := 12;  {1024x768x256}
+  i := vga_init;
+  StartupMode := vga_getcurrentmode;
+  vga_setmode(mode);
+  gl_setcontextvga(mode);
+  p := vga_getgraphmem; 
+  VideoMem := p;
+  modeinfo := vga_getmodeinfo(mode);
+  SeparateReadWriteWindows := (modeinfo^.flags and HAVE_RWPAGE <> 0);
+  if SeparateReadWriteWindows <> False then begin
+     vga_setcolor(14);
+     gl_fillbox(100,0,823,63,13);
+
+     DrawRectangle(100,0,923,63);
+     vga_setcolor(3);
+     vga_drawline(0,0,1023,767);
+     vga_drawline(1023,0,0,767);
+     for i := 0 to 5000000 do vga_drawpixel(10,10);  {delay}
+
+     Scroll;  {copy first 64 lines down to last 64 lines of screen}
+
+     for i := 0 to 5000000 do vga_drawpixel(10,10);  {delay}
+
+  end;
+   
+  vga_setmode(StartupMode);
+
+  writeln('SeparateReadWriteWindows = ',SeparateReadWriteWindows);
+  writeln('vgamode = ',mode);
+end.