Author: Ratko V Tomic
Date: 07:01:09 09/29/99
Go up one level in this thread
> The windows version seems to be more reasonable as it doesn't stuff > an unknown piece of software into memory and hook on to the timer > interrupt to check for moves by scanning video memory, etc. Windows version probably has to use Windows hooks (from Windows API), which has much more hook code overhead (on CPU speed) than a DOS hook of timer interrupt. This is due to much greater number of instructions for context switch in Windows (DOS needs only to push/pop registers) as well as protected mode overhead on every interrupt. The overall pure Windows background overhead on CPU, as tested with Rebel 8-10 running in stand-alone DOS vs in Windows DOS Box, with same hash tables (of various sizes) under windows, is about 5% drop in speed in DOS Box. As to checking video memory for moves, that seeems odd thing to do, when hooking interrupt 0x10 will do it much quicker, with no CPU overhead, other than checking 2 registers only within the individual output operation. If a DOS program is meant to run on a variety of graphics hardware, it would have to operate via int 0x10 for text output, at least in some types of program settings. I am also surprised that CM6000 is not auto232 compatible, since it takes coordinate format moves as kbd messages and outputs them in the coordinate format to a named window. Both of those can be easily monitored (or stuffed as the kbd messages). The only issue is that one would need a configuration utility that finds out and saves for the autoplayer the names of the windows for output and input (as well as program/module name). This utility would be run once for given machine & chess program and user would set-up chess program for coordinate notation and then play few moves using keyboard input for moves (mouse can be monitored and fed clicks and movement, too, but sending moves that way is obviously more involved and much more program specific).
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