Data processing systems

A data processing system, comprising:

• an execution pipeline, the execution pipeline comprising a programmable execution unit that executes program instructions to perform data processing operations;
• and
• processing circuitry configured to:
• issue to the programmable execution unit of the execution pipeline a program to be executed by the programmable execution unit that comprises a sequence of instructions to be executed by the programmable execution unit when executing the program;
• and wherein:
• the execution pipeline comprises processing circuitry configured to:
• issue one or more execution threads to the programmable execution unit for which the program is to be executed for execution;
• and
• the programmable execution unit of the execution pipeline comprises:
• processing circuitry operable to, when the programmable execution unit is executing a program that comprises a sequence of instructions to be executed by the programmable execution unit,
• execute the instructions of a group of instructions of the sequence of instructions of the program atomically, wherein the processing circuitry of the programmable execution unit comprises a functional unit that is operable to execute one instruction in an execution cycle;
• and
• a feedback circuit configured to feedback the output from the functional unit executing an instruction in a group of instructions that is being executed atomically directly for use as an input to the same functional unit when the functional unit is executing another instruction in the group of instructions that is being executed atomically.

A method of operating a programmable execution unit of a data processing unit that executes program instructions to perform data processing operations, wherein the programmable execution unit comprises a functional unit that is operable to execute one instruction in an execution cycle, the method comprising:

• the programmable execution unit when executing a program for an execution thread, the program comprising a sequence of instructions to be executed by the programmable execution unit when executing the program:
• executing at least one group of instructions of the sequence of instructions for the program atomically;
• and
• feeding back an output from the functional unit executing an instruction in the group of instructions that is being executed atomically directly for use as an input to the same functional unit when the functional unit is executing another instruction in the group of instructions that is being executed atomically.

A method of operating an execution pipeline of a data processing system, which execution pipeline includes a programmable execution unit that executes program instructions to perform data processing operations, wherein the programmable execution unit comprises a functional unit that is operable to execute one instruction in an execution cycle, the method comprising:

• issuing to the programmable execution unit a program to be executed by the programmable execution unit, the program comprising a sequence of instructions to be executed by the programmable execution unit when executing the program;
• issuing one or more execution threads for which the program is to be executed to the programmable execution unit for execution;
• and
• executing the program for the execution thread or threads;
• wherein:
• executing the program for the execution thread or threads comprises:
• executing at least one group of instructions of the sequence of instructions for the program atomically;
• and
• feeding back an output from the functional unit executing an instruction in the group of instructions that is being executed atomically directly for use as an input to the same functional unit when the functional unit is executing another instruction in the group of instructions that is being executed atomically.

A non-transitory computer readable storage medium storing computer software code which when executing on a processor performs a method of operating a programmable execution unit of a data processing unit that executes program instructions to perform data processing operations, wherein the programmable execution unit comprises a functional unit that is operable to execute one instruction in an execution cycle, the method comprising:

• the programmable execution unit when executing a program for an execution thread, the program comprising a sequence of instructions to be executed by the programmable execution unit when executing the program:
• executing at least one group of instructions of the sequence of instructions for the program atomically;
• and
• feeding back an output from the functional unit executing an instruction in the group of instructions that is being executed atomically directly for use as an input to the same functional unit when the functional unit is executing another instruction in the group of instructions that is being executed atomically.