How many processors have hardware support for loops ? I expect it to be a different, more efficient infrastructure than Comparison/Jump, maybe something similar to DisplayLists in old OpenGL ?
* Register rotation [1]: referenced registers inside the loop are cycled on each iteration
* Branch prediction [2]: with a dedicated loop count register, the CPU can tell with complete certainty when not to take the jump to the beginning (no mispredictions at the exit)
[1] http://www.cs.nmsu.edu/~rvinyard/itanium/register_rotation.h...