Container-based instruction set

Abstract

An apparatus comprises: front end circuitry configured to fetch and decode instructions; and processing circuitry configured to perform data processing operations in response to instructions fetched and decoded by the front end circuitry. In a container-based instruction set mode for processing instructions from a fixed-length instruction set for which each instruction of the fixed-length instruction set is encoded using the same number of functional bits representing functionality of the instruction, the front end circuitry is configured to decode the instructions according to an encoding scheme in which each instruction is required to meet an architectural encoding constraint requiring that, for a given instruction processed in the container-based instruction set mode: the given instruction is one of a plurality of instructions encoded fully within a C-bit container, where C is a fixed power-of-2 integer; each instruction has W functional bits, where W is a fixed non-power-of-2 integer; and no valid instruction is allowed to cross a boundary between C-bit containers. The front end circuitry supports a branch operation specifying as a branch target any one of the plurality of instructions encoded within a given C-bit container.

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