ALLOCATION OF COUNTERS FROM A POOL OF COUNTERS TO TRACK MAPPINGS OF LOGICAL REGISTERS TO PHYSICAL REGISTERS FOR MAPPER BASED INSTRUCTION EXECUTIONS

摘要

A mapper unit of an out-of-order processor assigns a particular counter currently in a counter free pool to count a number of mappings of logical registers to a particular physical register from among multiple physical registers, responsive to an execution of an instruction by the mapper unit mapping at least one logical register to the particular physical register. The number of counters is less than the number of physical registers. The mapper unit, responsive to the counted number of mappings of logical registers to the particular physical register decremented to less than a minimum value, returns the particular counter to the counter free pool.