A system and method for memory structures for efficient tracking and recycling
of physical register assignments are disclosed. The method and system provide the
necessary functionality to allow the number of physical registers assigned to incoming
instructions to equal the number of physical registers that are returned to the
list of free registers each cycle, thereby maintaining a substantially constant
number of physical register pointers in the list of free registers. The system
and method reduce the size of the memory structures utilized to track the usage
of physical registers and the recycling of these registers.