Operand supply to an execution unit

A method of processing data, said method comprising the steps of:

• storing within a register bank having a plurality of registers data values to be manipulated, said register bank having X read ports, where X is an integer greater than 1, for allowing simultaneous reading of data values from X registers during a read cycle;
• performing with an execution unit coupled to said X read ports at least one data processing operation, specified by a data processing instruction, that requires Y input operands from Y registers, where Y is greater than X and where said data processing instruction specifies which Y registers are to supply said Y input operands;
• storing within one or more cache registers as cached data values copies of data values stored within one or more corresponding ones of said plurality of registers of said register bank;
• and
• detecting, with a cache register controller coupled to said one or more cache registers, if said data processing instruction specifies within said Y input operands any data values stored in a register of said register bank of which a copy is stored in said one or more cache registers as a cached data value, and, if so, supplying said cached data value to said execution unit as said one of said Y input operands rather than reading said data value from said register bank, whereby the number of data values that require reading from said register bank via said X read ports is reduced.