From 31b108c7bb1d44cdc4b94b383c29a283272f4bd0 Mon Sep 17 00:00:00 2001 From: Jeroen Janssen Date: Fri, 8 Mar 2002 20:31:41 +0000 Subject: - adding some text about how banks work --- vbe_display_api.txt | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'vbe_display_api.txt') diff --git a/vbe_display_api.txt b/vbe_display_api.txt index 94adcce..a04a25f 100644 --- a/vbe_display_api.txt +++ b/vbe_display_api.txt @@ -131,7 +131,24 @@ API * VBE_DISPI_INDEX_BANK : WORD This parameter can be used to read/write the current selected BANK (at 0xA0000). This can be used for switching banks in banked mode. + + +Displaying GFX +-------------- + Currently Linear Frame Buffer support is not available yet. + The only other way of displaying (VBE) graphics is using banked modi. + + What happens is that the total screen is devided in banks of 'VBE_DISPI_BANK_SIZE_KB' KiloByte in size. + If you want to set a pixel you can calculate its bank by doing: + + offset = pixel_x + pixel_y * resolution_x; + bank = offset / 64 Kb (rounded 1.9999 -> 1) + bank_pixel_pos = offset - bank * 64Kb + + Now you can set the current bank and put the pixel at VBE_DISPI_BANK_ADDRESS + bank_pixel_pos + + Notes ----- * Currently only Banked modi are 'officially' supported (although 320x200x8 LFB is available in the bios atm). -- cgit v1.2.1