Mode-x resolution instability

[Reality Interactive]

Hi all

We are almost finished development of an "awesome" (hehe) new scrolling
game, Cyril Cyberpunk, but we are concerned about the stability of the
mode-x tweak we are using.

We have access to a range of video cards, including Tseng, Cirrus Logic,
Trident, Oak, the S3 range, but obviously there are thousands of
other cards out there that may or may not be able to handle the
resolution.

If anyone knows of any compatibility problems with the following res:

real res: 288x224, 24 split screen

Set up as follows:

;------------------------------------------------------------------------
set_scroll_mode_ proc near

pusha

mov ah, 00h
mov al, 13h
int 10h ; set mode 13h

mov dx, SEQ_ADDR
mov ax, 0604h
out dx, ax ; turn off chain-4

mov dx, MISC_OUT
mov al, 0E3h
out dx, al ; 480 scan lines at 25 Hz

mov dx, CRTC_ADDR
mov edi, offset crtc_data
mov cx, 16

set_crtc_reg:
mov ax, [edi] ; crtc index+value
out dx, ax
add edi, 2
loop set_crtc_reg

mov al, 07h
out dx, al
inc dx
in al, dx
or al, 10h
out dx, al ; turn on bit 9 of line compare

dec dx
mov al, 09h
out dx, al
inc dx
in al, dx
and al, 191
out dx, al ; max scan lines+line compare

mov dx, 3dah
in al, dx ; set to address mode

mov dx, 3c0h
mov al, 10h ; mode control+BIT 5 = 0
out dx, al

mov dx, 3c1h ; vga
in al, dx
or al, 00100000b ; SET PEL PANNING COMPATIBLITY
push ax ; save value

mov dx, 3dah
in al, dx ; back for write

mov dx, 3c0h
mov al, 10h ; BIT 5 TO 1
out dx, al ; BACK TO NORMAL

pop ax
out dx, al

mov dx, 3dah
in al, dx
mov dx, 3c0h
mov al, 20h
out dx, al

popa

ret

set_scroll_mode_ endp

;------------------------------------------------------------------------

please mail us direct at: stu...@aztec.co.za as soon as possible, and
tell us about it.

Also, if you are interested to see what we are up to, mail us for
a preview, or a non-interactive demo.

Alternatively, check out our web site at:

Web: http://www.purple.co.uk/purplet/reality/

Thanks for your input.

REALITY INTERACTIVE

+----------------------------------+-----------------------------------+
| | EMail: stu...@aztec.co.za |
| Senior Programming Team | |
| | Tel: +27 21 616 462 |
+----------------------------------+-----------------------------------+
| R E A L I T Y I N T E R A C T I V E |
| Web: http://www.purple.co.uk/purplet/reality/ |
| Mail: rea...@aztec.co.za Tel: +27 21 616 462 Fax: +27 21 683 4203 |
| P.O. Box 2036, Clareinch 7740, Cape Town, South Africa |
+----------------------------------------------------------------------+