Abstract: In a microprocessor, an instruction scheduler 30 includes a dependency matrix 36 and a waiting buffer 34. A dependency determination unit 32 receives instructions to be executed, forwards the instructions to the waiting buffer 34, determines if any dependency exists between the instructions, and forwards the dependency information to the dependency matrix 36 in the form of a dependency vector 40. The dependency matrix 36 periodically determines whether any of the instructions contained in the waiting buffer 34 are ready to be executed, that is, no dependencies exist for that instruction. As each instruction is dispatched for execution from the waiting buffer 34, the dependency vector 40 for all dependent instructions is cleared for subsequent execution. In this manner, an out-of-order processing scheme is implemented that efficiently accounts for data dependency between processed instructions.

Abstract: A method for scheduling a flag generating instruction and a subsequent instruction. The subsequent instruction has a data dependency on the flag generating instruction. The flag generating instruction is translated into first and second instructions. The subsequent instruction is translated into at least a third instruction. The first instruction, when executed, generates a result and intermediate flag generation data. The second instruction, when executed, generates a plurality of flags. The first instruction is scheduled to execute before the second and third instructions. The second instruction is scheduled to execute before the third instruction if the third instruction has a data dependency on the second instruction, otherwise the third instruction may be scheduled to execute before the second instruction.

Abstract: In a microprocessor, an Instruction scheduler 30 includes a dependency matrix 36 and a waiting buffer 34. A dependency determination unit 32 receives instructions to be executed, forwards the instructions to the waiting buffer 34, determines if any dependency exists between the instructions, and forwards the dependency information to the dependency matrix 36 in the form of a dependency vector 40. Dependency matrix 36 periodically determines whether any of the instructions contained in the waiting buffer 34 are ready to be executed, that is, no dependencies exist for that instruction. All identified instructions are then assigned to a current wave to be dispatched. The identified instructions are then dispatched for execution as execution resources become available. As each instruction is dispatched for execution in the waiting buffer 34, the dependency vector 40 for all dependent instructions is cleared for subsequent execution.