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Re: MS-DOS direct screen output - native and in a window

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James Harris wrote:
> ...
> However, how should things like the screen size (rows and columns) be
> determined? I know there is a BIOS call int 0x10-0f to get the columns but
> not the rows.

Here's how I did it.


        mov     ax,0500h                ; set video page = 0
cold1:  call    video
        call    gmode                   ; get video mode
        cmp     al,7                    ; 80 col mono
        jz      cold2
        cmp     al,3                    ; 80 col color
        jz      cold2
        cmp     al,2                    ; 80 col b/w
        jz      cold2
        mov     ax,3                    ; set video mode = 80 col color
        jmp     cold1                   ; (screen will blank)
cold2:  dec     bh                      ; cols
        mov     wmax,bh
        sub     bh,bh
        sub     dl,dl                   ; assume old CGA card
        mov     ax,1130h
        call    video
        or      dl,dl                   ; rows if EGA+
        jnz     cold3
        mov     dl,24
cold3:  mov     wmax+1,dl
        ...


;       get video mode  AL=mode AH=page BH=cols

gmode:  mov     ah,0fh
        call    video
        xchg    bh,ah
        mov     word ptr cmode,ax       ; save
        ret

video:  push    si
        push    bp
        int     10h
        pop     bp
        pop     si
        ret

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Thread

MS-DOS direct screen output - native and in a window "James Harris" <james.harris.1@gmail.com> - 2013-08-29 10:10 +0100
  Re: MS-DOS direct screen output - native and in a window "R.Wieser" <address@not.available> - 2013-08-29 12:58 +0200
  Re: MS-DOS direct screen output - native and in a window "Bill Buckels" <bbuckels@mts.net> - 2013-08-29 05:59 -0500
    Re: MS-DOS direct screen output - native and in a window "Bill Buckels" <bbuckels@mts.net> - 2013-08-29 07:23 -0500
      Re: MS-DOS direct screen output - native and in a window "Bill Buckels" <bbuckels@mts.net> - 2013-08-29 08:35 -0500
  Re: MS-DOS direct screen output - native and in a window "Ed" <invalid@invalid.com> - 2013-09-28 20:34 +1000
    Re: MS-DOS direct screen output - native and in a window pete@nospam.demon.co.uk - 2013-09-29 06:45 +0000
      Re: MS-DOS direct screen output - native and in a window "Ed" <invalid@invalid.com> - 2013-09-29 19:33 +1000
        Re: MS-DOS direct screen output - native and in a window "James Harris" <james.harris.1@gmail.com> - 2013-09-29 16:06 +0100
          Re: MS-DOS direct screen output - native and in a window "Ed" <invalid@invalid.com> - 2013-10-01 11:28 +1000

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