- preparing docs for new DISPI interface (for hardware scrolling)

1 files changed, 49 insertions, 18 deletions

diff --git a/vbe_display_api.txt b/vbe_display_api.txt
index b866e67..3c90d47 100644
--- a/vbe_display_api.txt
+++ b/vbe_display_api.txt
@@ -12,8 +12,8 @@ VBE Display API
 
 
 API History
------------
-0xb0c0            supports the following VBE_DISPI_ interfaces (present in Bochs 1.4.pre2):
+-----------                
+0xb0c0            supports the following VBE_DISPI_ interfaces (present in Bochs 1.4):
                   VBE_DISPI_INDEX_ID
                   VBE_DISPI_INDEX_XRES
                   VBE_DISPI_INDEX_YRES
@@ -23,11 +23,21 @@ API History
                   
                   Bpp format supported is:
                   VBE_DISPI_BPP_8
-                  
+
+0xb0c1            supports 0xb0c0 VBE_DISPI_ interfaces, additional interfaces:
+                  VBE_DISPI_INDEX_VIRT_WIDTH
+                  VBE_DISPI_INDEX_VIRT_HEIGHT
+                  VBE_DISPI_INDEX_X_OFFSET
+                  VBE_DISPI_INDEX_Y_OFFSET
+                 
                   
 
 History
 -------
+  Version 0.6     (UNRELEASED)  Jeroen Janssen
+                  - Added LFB support
+                  - Added Virt width, height and x,y offset
+                  
   Version 0.5     2002 March 08   Jeroen Janssen
                   - Added documentation about panic behaviour / current limits of the data values.
                   - Changed BPP API (in order to include future (A)RGB formats)
@@ -36,13 +46,11 @@ History
 
 Todo
 ----
-  Version 0.5     - Update the VBEBios with the new API in this spec
-                  - Update the Bochs display patch with the new API in this spec + add this document.
+  Version 0.6     - add virtual width, height, x offset, y offset in bios & bochs
+                    (for set/get logical scan line length andset/get display start)
   
-  Version 0.5+    [random order]
+  Version 0.6+    [random order]
                   - Add lots of different (A)RGB formats
-                  - Add Linear Frame Buffer API
-
   
 References
 ----------
@@ -84,8 +92,13 @@ Abbreviations
   #define VBE_DISPI_INDEX_BPP             0x3
   #define VBE_DISPI_INDEX_ENABLE          0x4
   #define VBE_DISPI_INDEX_BANK            0x5
+  #define VBE_DISPI_INDEX_VIRT_WIDTH      0x6
+  #define VBE_DISPI_INDEX_VIRT_HEIGHT     0x7
+  #define VBE_DISPI_INDEX_X_OFFSET        0x8
+  #define VBE_DISPI_INDEX_Y_OFFSET        0x9
   
   #define VBE_DISPI_ID0                   0xB0C0
+  #define VBE_DISPI_ID1                   0xB0C1
   
   #define VBE_DISPI_BPP_8                 0x0
 // The following is not support yet, but just for reference available.  
@@ -102,8 +115,9 @@ API
   The display api works by using a index (VBE_DISPI_IOPORT_INDEX) and 
   data (VBE_DISPI_IOPORT_DATA) ioport. One writes the index of the parameter to the index port.
   Next, the parameter value can be read or written.
-  
-  * VBE_DISPI_INDEX_ID  : WORD
+
+[0xb0c0]
+  * VBE_DISPI_INDEX_ID  : WORD {R,W}
     This parameter can be used to detect the current display API (both bochs & vbebios).
     The bios writes VBE_DISPI_ID0 to the dataport and reads it back again.
     This way, the display code knows the vbebios 'ID' and the vbebios can check if the correct
@@ -113,7 +127,7 @@ API
     
     Example values: VBE_DISPI_ID0
         
-  * VBE_DISPI_INDEX_XRES : WORD
+  * VBE_DISPI_INDEX_XRES : WORD {R,W}
     This parameter can be used to read/write the vbe display X resolution (in pixels).
     It's illegal to set the XRES when the VBE is enabled (display code should generate PANIC).
     
@@ -121,7 +135,7 @@ API
     
     Example values:   320,640,800,1024
 
-  * VBE_DISPI_INDEX_YRES : WORD
+  * VBE_DISPI_INDEX_YRES : WORD {R,W}
     This parameter can be used to read/write the vbe display Y resolution (in pixels).
     It's illegal to set the YRES when the VBE is enabled (display code should generate PANIC).
     
@@ -129,7 +143,7 @@ API
     
     Example values:   200,400,480,600,768
   
-  * VBE_DISPI_INDEX_BPP : WORD
+  * VBE_DISPI_INDEX_BPP : WORD {R,W}
     This parameter can be used to read/write the vbe display BPP.
     It's illegal to set the BPP when the VBE is enabled (display code should generate PANIC).
     
@@ -137,7 +151,7 @@ API
     
     Example values:   VBE_DISPI_BPP_8
     
-  * VBE_DISPI_INDEX_ENABLE : WORD
+  * VBE_DISPI_INDEX_ENABLE : WORD {R,W}
     This parameter can be used to read/write the vbe ENABLED state.
     If the bios writes VBE_DISPI_ENABLED then the display code will setup a hostside display mode 
     with the current XRES, YRES and BPP settings.
@@ -145,10 +159,29 @@ API
     
     Example values: VBE_DISPI_ENABLED, VBE_DISPI_DISABLED
   
-  * VBE_DISPI_INDEX_BANK : WORD
+  * VBE_DISPI_INDEX_BANK : WORD {R,W}
     This parameter can be used to read/write the current selected BANK (at 0xA0000).
     This can be used for switching banks in banked mode.
 
+[0xb0c1]
+  * VBE_DISPI_INDEX_VIRT_WIDTH : WORD {R,W}
+    This parameter can be used to read/write the current virtual width.
+    Upon enabling a mode, this will be set to the current xres
+    Setting this field during enabled mode will result in the virtual width to be changed.
+    Value will be adjusted if current setting is not possible.
+  
+  * VBE_DISPI_INDEX_VIRT_HEIGHT : WORD {R}
+    This parameter can be read in order to obtain the current virtual height.
+    This setting will be adjusted after setting a virtual width in order to stay within limit of video memory.
+    
+  * VBE_DISPI_INDEX_X_OFFSET : WORD {R,W}
+    The current X offset (in pixels!) of the visible screen part.
+    Writing a new offset will also result in a complete screen refresh.
+
+  * VBE_DISPI_INDEX_Y_OFFSET : WORD {R,W}
+    The current Y offset (in pixels!) of the visible screen part.
+    Writing a new offset will also result in a complete screen refresh.
+
 
 Displaying GFX
 --------------
@@ -167,9 +200,7 @@ Displaying GFX
 
 
 Notes
------
-  * Currently only Banked modi are 'officially' supported (although 320x200x8 LFB is available in the bios atm).
-   
+----- 
   * Since the XRES/YRES/BPP may not be written when VBE is enabled, if you want to switch from one VBE mode
     to another, you will need to disable VBE first.