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CICA 1993 April
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CICA MS Windows - April 1993.iso
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1992-09-22
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9-22-92
*** SVGA.DLL ***
This DLL is designed to support ALL video cards. The preformance of
this DLL is slightly less than the card-specific DLLs but it has a
broader range. If there is a specific DLL that supports your card,
then you should use that one, since it will probably be faster than
this one.
This DLL will support any Video card/mode using some undocumented
Windows functions that force the Windows display driver to do the mode
switching. The Windows screen is saved into a full screen sized
bitmap using the BitBlt API call. It also uses 2 DCs throughout the
life of the debugger, so if you use more than 2-3 DCs in your program
and you see weird things happening, then you'll want to disable the
BitBlt option below. On Coprocessor cards (or those that are
advertised as "Windows Accelerators") the responce time is fairly
quick even in 1024x768 modes. On non-coprocessor cards, the higher
the resolution, the longer it will take for the screen switch to
occure. (By screen switch, I mean the transition from the Windows
screen to the Debugger screen and/or vice versa.) There are some
options that can be specified in the TDW.INI file under the
[VideoOptions] section, that may help improve preformance:
BitBlt=Y|N - Y saves the bitmap, N doesn't.
This is on by default and only needs to be
specified in order to disable it. If disabled,
it prevents the DLL from allocating the bitmap,
the DCs or from saving the entire screen each
screen swap. If you disable this, you will not
see anything on the user screen (Alt-F5) until
you run the program and control goes back to
Windows.
ForceRepaint=Y|N - Y Forces Windows to repaint the screen, N doesn't.
This option is on by default and only takes
effect if BitBlt disabled. This is what forces
Windows to repaint the whole screen when your
program is run and you are not saving the whole
screen in the bitmap. If you disable this
option, you won't see anything on the Windows
screen until your program invalidates something
and repaints it.
ROWS=xx 25, 43, or 50 rows on the screen. Warning: TDW
will abide by this number, so don't specify
something that your screen will not handle.
XGA=Y|N - Set this to 'Y' only on an XGA card.
On XGA, TIGA, and other high powered coprocessor cards, the BitBlt
option should be fast enough to use pleasantly.
Known problems: None, the XGA problem has been fixed. If the XGA=Yes
switch is enabled, then TDW will behave in all XGA
modes. The mouse can now be used as usual.
-- Jeff Peters