ARITHMETIC PROCESSING UNIT

摘要

PURPOSE:To reduce the cost and to improve the performance with an arithmetic processor by performing the transfer of data between a register file and a memory based on the difference between the start address of a register window used by a procedure under execution and the head address of the register file. CONSTITUTION:A comparator 6 compares the difference between the start address of a register window used by a procedure under execution supplied from a counter 5 and the head address of a register file with a prescribed constant and produces a signal to show the possibility of both overflow and underflow states. A control logic circuit 3 performs the transfer of data between the register file and a stack in response to the signal produced by the comparator 6. Thus it is possible to suppress the occurrence of both overflow and underflow states without increasing the scale of the register file. Then, the deterioration of performance due to the overflow and underflow states can be prevented.