Synchronized register renaming between a master processor and a
coprocessor that receives operations from the master enables efficient
implementation of register renaming and operation execution in the
processors. An ideal and an external register allocation map are
implemented in the coprocessor. When registers are no longer allocated
according to the ideal allocation map and the registers are currently
allocated according to the external allocation map, the registers are
deallocated in the external map and the number of freed registers is
reported to the master. The master increments a free register credit
count accordingly, and decrements the credit count by one for each
operation issued to the coprocessor. An operation is not issued to the
coprocessor unless at least a register is free according to the credit
count. The master also throttles coprocessor operation issue based on a
credit count corresponding to free scheduler entries available in the
coprocessor.