Secondary reorder buffer microprocessor

• Main Author: KAHLE JAMES ALLAN
• Format: Patent
• Language: English
• Published: 30.09.2003
• Edition: 7
• Subjects: CALCULATING; COMPUTING; COUNTING; ELECTRIC DIGITAL DATA PROCESSING; PHYSICS

A method, processor, and data processing system for enabling maximum instruction issue despite the presence of complex instructions that require multiple rename registers is disclosed. The method includes allocating a first rename register from a first reorder buffer for storing the contents of a first register affected by the complex instruction. A second rename register from a second reorder buffer is then allocated for storing the contents of a second register affected by the complex instruction. In an embodiment in which the first reorder buffer supports a maximum number of allocations per cycle, the allocation of the second register using the second reorder buffer prevents the complex instruction from requiring multiple allocation slots in the first reorder buffer. The method may further include issuing a second instruction that contains a dependency on a register that is allocated in the secondary reorder buffer. In one embodiment, reorder buffer information indicating the second instruction's dependence on a register allocated in the secondary reorder buffer is associated with the second instruction such that, when the second instruction is issued subsequently, the reorder buffer information is used to restrict the issue unit to checking only the secondary reorder buffer for dependencies.