Decoding instructions that are modified by one or more other instructions

A device arranged to store a computer program, the computer program comprising a plurality of instructions, the device comprising:

• a program memory;
• and
• a processor configured to:
• receive the plurality of instructions, the plurality of instructions comprising one or more base instructions and at least one modifier instruction for each base instruction,
• analyze the plurality of instructions to identify each base instruction and the at least one modifier instruction for each identified base instruction, and
• store each identified base instruction on a same side of a boundary within the program memory as the at least one modifier instruction for that identified base instruction wherein the processor is configured to store each identified base instruction on the same side of a boundary within the program memory as the at least one modifier instruction for that identified base instruction by reordering the plurality of instructions so that each identified instruction is stored on the same side of a boundary within the program memory as the at least one modifier instruction for that identified base instruction.

A data processing apparatus arranged to execute a computer program, the data processing apparatus comprising:

• a program memory configured to store the computer program, the computer program comprising a plurality of instructions, the plurality of instructions comprising one or more base instructions and at least one modifier instruction for each base instruction, the plurality of instructions stored in the program memory so that each base instruction is stored on a same side of a boundary within the program memory as the at least one modifier instruction for that base instruction;
• a program counter configured to identify a first instruction in the program memory;
• a fetch unit configured to retrieve the first instruction in the program memory identified by the program counter;
• and
• a decode unit configured to:
• receive the first instruction from the fetch unit, and
• request an additional instruction from the fetch unit to look for a modifier instruction for the first instruction, the additional instruction being an instruction immediately preceding the first instruction in the program memory or an instruction immediately following the first instruction in the program memory;
• wherein the fetch unit is further configured to determine whether the additional instruction is on the same side of a boundary of the program memory as the first instruction, and in response to determining that the additional instruction is not on the same side of the boundary of the program memory, avoid fetching the additional instruction from the program memory.