Mail Archives: djgpp/1994/01/08/17:18:08
> Offhand I do not know if the 486 has a prefetch queue in addition to its
> internal cache; it seems that the cache would make a prefetch queue
> unnecessary, though.
The 486 does have a prefetch queue. It seems to be 32 bytes deep. This broke
some versions of the DIET file compressor which had self-modifying code which
patched in a jump address exactly 32 bytes away from the patching code. Only
some compressed programs failed, and single stepping with a debugger made them
work. (The program which I use to duplicate shareware disks for my customers
was the one which broke. It took a long time to figure out why.)
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