|Variable DMA Refresh adjuster (ASM/COM/DOC files provided).|
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Download File SFREAK.ZIP Here
Contents of the SFREAK.DOC file
I had just started my 8088 Assembly programming when I came
accross the program SPEEDER. I learned that Tom was canging the
refresh from 0012H to 0040H in order to get the processor freed
up to do the things it should be vice waiting for the refresh to
get done. Always one to expiriment, I found that I could adjust
the refresh on my XT clone out to F000H (for a while). The speed
difference between 0040H and 0F00H (my safety zone speed) is not
great; but it drops my SPEED99 loop time from 316ms to 312ms.
The major improvement the I have added is the ability to
specify the refresh rate from the command line. This should make
it easier to expiriment on your machine to find your safety zone.
I recommend slowly increasing the rate devisor until you START to
crash - then divide by 16 (shift one digit to the right).
On the command line, you can enter either 2 or 4 hex digits.
If you enter two (or three having it ignore the third digit) it
assumes 00H for the high byte.
January 7, 2018 Add comments