Fun with movsb and prefetch

Originally Posted by WARM3CH

ah, good old pre-fetch queue. It's been a while...
Now, here is small challenge: Write an assembly program to find out how long is the prefetch queue of your CPU! I used to give this as an exercise to my system-level programming students. Some of them could find the solution in just a few CPU cycles and some crashed like an old Pentium

Sorry for my terrible English. Why emphasize "old Pentium" ?
p.s. the prog running smoothly with Pentium 4 2.8G w/ HT