Re: Asm graphics

 BBS: Inland Empire Archive
Date: 03-23-93 (21:31)             Number: 331
From: BOB SEWELL                   Refer#: NONE
  To: RICH GELDREICH                Recvd: NO  
Subj: Re: Asm graphics               Conf: (2) Quik_Bas

 In what possibly was a momentary lapse of reason, Rich Geldreich said:

 RG>    It sounds like you're not resetting everything back to what QB
 RG> expects it to be. I never could remember that they're called, but are
 RG> you messing with port 03C4h and port 03C5h, the write plane select
 RG> register? QB expects that to be set to 0Fh, or otherwise everything
goes

     Actually, it's ports 03ceh and 03cfh. I'll post the code that sets and
(supposedly) resets these ports.

        mov     dx, 3ceh         ; prep EGA register to set mode
        mov     al, 5            ;              "
        out     dx, al           ;              "
        inc     dx               ; set EGA graphics write mode 2
        mov     ax, 2            ;              "
        out     dx, al           ;              "

        mov     dx, 3ceh         ; prep EGA register to set mode
        mov     ax, 5            ;              "
        out     dx, al           ;              "
        xor     ax, ax           ; set EGA write mode 0
        inc     dx               ;              "
        out     dx, al           ;              "

     So, you think maybe that last "out" should be with a 0fh rather than a
0h in the AL register?


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