Apple Inc.

Zhaoxiang Jin

Francesco Spadini

Skanda K Srinivasa

John D Pape

Haoyan Jia

Brian T Mokrzycki

Reena Panda

Milos Becvar

Techniques are disclosed that relate to fusing operations for execution of certain instructions. A processor may include a first execution circuit, of a first type, coupled to a first register file, a second execution circuit, of a second type, coupled to a second register file and a load/store circuit coupled to the first and second register files. The load/store circuit includes an issue port configured to receive an instruction operation for execution, a memory execution circuit configured to execute memory access operations, and a register transfer execution circuit. The register transfer execution circuit is configured to execute instruction operations specifying data transfer from the first register file to the second register file and an operation to be performed using the data, and the load/store circuit is configured to direct a given instruction operation from the issue port to one of the memory execution circuit or the register transfer execution circuit.

Operation fusion for instructions bridging execution unit types

Techniques are disclosed that relate to executing pairs of instructions. A processor may include fusion detector circuitry configured to detect a pair of fetched instructions and fuse the pair of fetched instructions into a fused instruction operation, and execution circuitry coupled to the fusion detector circuitry and configured to execute the fused instruction operation. In some embodiments the pair of instructions is executable to generate a remainder of a division operation. In some embodiments the pair of instructions is executable to compare two operands and perform a write operation based on the comparison. In some embodiments the pair of instructions is executable to perform an operation and apply a mask bit sequence to the result. The fusion detector circuitry may also be configured to obtain first and second portions of a constant value from first and second instructions and store the first and second portions in a destination register.

Instruction fusion

An apparatus includes a rescue buffer circuit, a store queue circuit, and a control circuit. The rescue buffer circuit may be configured to retain address information related to store instructions. The store queue circuit may be configured to buffer dependency information related to a particular store instruction until the particular store instruction is released to be executed. The control circuit may be configured to cause a subset of the dependency information for the particular store instruction to be written to the rescue buffer circuit. The rescue buffer circuit may be configured to retain the subset after the dependency information has been released from the store queue circuit, and to perform a subsequent load instruction corresponding to a memory location associated with the particular store instruction using the subset of the dependency information from the rescue buffer circuit.

Stack pointer instruction buffer for zero-cycle loads

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Austin, TX, United States of America

Zhaoxiang Jin