source: trunk/BOOTCODE/SPECIAL/CHARSET.ASM@ 47

; AiR-BOOT (c) Copyright 1998-2008 M. Kiewitz
;
; This file is part of AiR-BOOT
;
; AiR-BOOT is free software: you can redistribute it and/or modify it under
;  the terms of the GNU General Public License as published by the Free
;  Software Foundation, either version 3 of the License, or (at your option)
;  any later version.
;
; AiR-BOOT is distributed in the hope that it will be useful, but WITHOUT ANY
;  WARRANTY: without even the implied warranty of MERCHANTABILITY or FITNESS
;  FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
;  details.
;
; You should have received a copy of the GNU General Public License along with
;  AiR-BOOT. If not, see <http://www.gnu.org/licenses/>.
;
;---------------------------------------------------------------------------
;                                                AiR-BOOT / CHARSET SUPPORT
;---------------------------------------------------------------------------

; This file is only included, when compiling versions that are meant to
;  contain special characters that are not included in the Video ROM charset.

; May destroy all-purpose registers (AX,BX,CX,DX), will preserve all others
CHARSET_IncludeCyrillic        Proc Near  Uses si di bp
   ; First we get the ROM charset from BIOS...
   mov    ax, 1130h
   mov    bh, 6                          ; Get ROM VGA 25x80 charset
   int    10h                            ; VIDEO BIOS: Get charset table pointer
   mov    bx, ds                         ; ES:BP point to charset (in Video-ROM)
   mov    ax, es
   mov    es, bx
   mov    ds, ax
   mov    si, bp                         ; DS:SI - ROM Font 25x80 and ES==CS
   mov    di, offset CharsetTempBuffer
   mov    cx, 2048
   rep    movsw                          ; Copy ROM-charset to Temp-Buffer
   mov    ds, bx                         ; DS==CS
   mov    si, offset CHARSET_Cyrillic
   mov    di, offset CharsetTempBuffer+2048

   mov    dl, 64                         ; Decode 64 character bitmaps
   xor    al, al
   xor    ch, ch
  DecodeLoop:                            ; This is an uncompressing-loop
      mov    ah, ds:[si]
      inc    si
      mov    cl, ah
      and    cl, 0Fh
      rep    stosb                       ; Write NULs, count: lower 4 bits
      mov    cl, ah
      shr    cl, 4
      or     cl, cl
      jz     EndOfStream
      rep    movsb
      jmp    DecodeLoop
     EndOfStream:
      cmp    di, offset CharsetTempBuffer+3840
      jae    DecodeDone
      add    di, 768                     ; Skip 3x16 char blocks
      jmp    DecodeLoop
  DecodeDone:
   call   FX_WaitRetrace                 ; Wait for retrace to reduce flickering
   mov    ax, 1110h
   mov    bh, 16
   xor    bl, bl
   mov    cx, 0FFh
   xor    dx, dx
   mov    bp, offset CharsetTempBuffer ; ES:BP - New charset
   int    10h                            ; VIDEO BIOS: Set new charset table
   mov    ah, 12h
   mov    bl, 30h
   mov    al, 2                          ; 400 ScanLines
   int    10h                            ; VIDEO BIOS: Set Scanlines
   ret
CHARSET_IncludeCyrillic        EndP