Arm Limited

Mélanie Vincent

Cédric Denis Robert Airaud

Florent Begon

Norbert Bernard Eugene Lataille

Norbert Bernard Eugéne Lataille

Within a data processing system including a register renaming mechanism, register renaming for some conditional instructions which are predicted as not-executed is suppressed. The conditional instructions which are subject to such suppression of renaming may not be all conditional instructions, but may be those which are known to consume a particularly large number of physical registers if they are subject to renaming A conditional load multiple instruction in which multiple registers are loaded with new data values taken from memory in response to a single instruction is an example where the present technique may be used, particularly when one of the registers loaded is the program counter and accordingly the instruction is a conditional branch.

Suppressing register renaming for conditional instructions predicted as not executed

A data processing apparatussupports out-of-order processing register renaming using a renaming stage. A set of physical registersis mapped to architectural registers. Available-register identifying logicis used to identify which physical registersare available for use by the renaming stage. The available-register identifying logicincludes an instruction FIFOstoring register mapping data for unresolved instructions and indicating physical registersstoring data values which may be required in association with those unresolved speculative instructions. The speculative instructions may be predicted branch instructions, load/store instructions, conditional instructions or other types of instruction.

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Grasse, France

Mélanie Vincent