--- hatari/src/includes/vdi.h	2019/04/01 07:09:16	1.1
+++ hatari/src/includes/vdi.h	2019/04/09 08:53:20	1.1.1.10
@@ -1,20 +1,58 @@
 /*
-  Hatari
+  Hatari - vdi.h
+
+  This file is distributed under the GNU General Public License, version 2
+  or at your option any later version. Read the file gpl.txt for details.
 */
 
-#define MAX_VDI_WIDTH  1024
-#define MAX_VDI_HEIGHT  768
+#ifndef HATARI_VDI_H
+#define HATARI_VDI_H
+
 #define MAX_VDI_PLANES  4
+/* TOS needs screen width to be aligned to 128/planes and height to VDI text
+ * height (16, larger of these, is used in calculating the limits in Hatari).
+ * Max. screen size supported by EmuTOS (and TOS v3.x?) is 300kB.
+ *
+ * Below MAX_VDI_* values are reasonable limits for monochrome resolutions.
+ * 300kB limits screen size to max. resolution of 2048x1200 or 1920x1280,
+ * which allows FHD (1920×1080), WUXGA (1920x1200) and QWXGA (2048x1152)
+ * standard resolutions.
+ * 
+ * On 4-color mode, 300kB limits screen size to 1280x960 or 1200x1024
+ * which allows HD (1280x720), WXGA (1280x768) and XGA+ (1152x864)
+ * standard resolutions.
+ * 
+ * On 16-color mode, 300kB limits screen size to 1024x576 or 800x768,
+ * which fills nicely qHD (960x540), DVGA (960x640) and WSVGA (1024x600)
+ * standard resolution displays.
+ */
+#define MAX_VDI_BYTES 300*1024
+#define MAX_VDI_WIDTH  2048
+#define MAX_VDI_HEIGHT 1280
+/* smaller doesn't make sense even for testing */
+#define MIN_VDI_WIDTH   320
+#define MIN_VDI_HEIGHT  208
+
+
+enum
+{
+  GEMCOLOR_2,
+  GEMCOLOR_4,
+  GEMCOLOR_16
+};
+
+extern Uint32 VDI_OldPC;
+extern bool bUseVDIRes, bVdiAesIntercept;
+extern int VDIWidth,VDIHeight;
+extern int VDIRes,VDIPlanes;
+
+extern int VDI_Limit(int value, int align, int min, int max);
+extern void VDI_SetResolution(int GEMColor, int WidthRequest, int HeightRequest);
+extern void AES_Info(Uint32 bShowOpcodes);
+extern void VDI_Info(Uint32 bShowOpcodes);
+extern bool VDI_AES_Entry(void);
+extern void VDI_LineA(Uint32 LineABase, Uint32 FontBase);
+extern void VDI_Complete(void);
+extern void VDI_Reset(void);
 
-extern BOOL bHoldScreenDisplay;
-extern int LineABase,FontBase;
-extern unsigned int VDI_OldPC;
-extern BOOL bUseVDIRes;
-extern int VDIWidth,VDIHeight,VDIRes;
-extern int VDIPlanes,VDIColours,VDICharHeight;
-
-extern void VDI_SetResolution(int GEMRes,int GEMColour);
-extern BOOL VDI(void);
-extern void VDI_OpCode(void);
-extern void VDI_FixDesktopInf(void);
-extern void VDI_LineA(void);
+#endif  /* HATARI_VDI_H */