Power efficiency in microprocessor systems
AssigneeAT&T Laboratories-Cambridge Ltd.
InventorsPaul Webster, Phil Endecott
Life of this patent
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Abstract
Methods of reducing the power consumption of a microprocessor system, comprising a microprocessor and memory connected by a bus, are provided which involve optimising a program stored in the memory by rescheduling after linking, swapping equivalent instructions, or swapping the operands of commutative operations.
Claims15
A method of reducing the power consumption of a microprocessor system which comprises a microprocessor and a memory connected by at least one bus, said microprocessor being arranged to execute a program stored in said memory,
- said method comprising optimising said program by carrying out the following steps:
- a) producing a number of component programs each comprising a series of source code instructions,
- b) compiling each said component program to produce a number of compiled programs,
- c) linking said compiled programs to produce a linked program which comprises a series of instructions containing fully resolved symbols, and
- d) producing said program by performing code rescheduling on said series of instructions, so as to change an order of said instructions in order to reduce a hamming distance between consecutive ones of said instructions.
A method of reducing the power consumption of a microprocessor system which comprises a microprocessor and a memory connected by at least one bus, said microprocessor being arranged to execute a program stored in said memory,
- said method comprising optimising said program by carrying out the following steps:
- a) for each instruction of said program, considering possible alternative instructions which could be substituted for said instruction without changing an operation of said program,
- b) for each such possible alternative instruction, considering how a use of said alternative instruction would affect a hamming distance between consecutive instructions, and
- c) selecting said instruction which results in a lowest overall hamming distance when said program is executed.
A method of reducing the power consumption of a microprocessor system which comprises a microprocessor and a memory connected by at least one bus, said microprocessor being arranged to execute a program stored in said memory,
- said method comprising optimising said program by carrying out the following steps:
- a) identifying those instructions of said program which involve a commutative operation,
- b) for such instructions, considering the effect of swapping operands of said commutative operation on a hamming distance between consecutive ones of said instructions, and
- c) selecting an order of said operands which results in a lowest overall hamming distance when said program is executed.
Dependencies are inferred from the claim text.