Abstract: At least one instruction of a sequence of program instructions has a plurality of alternative outcomes including at least a first outcome that is independent of at least one operand and a second outcome that is dependent on the at least one operand. The at least one operand is a value generated by a preceding instruction in the sequence. The instruction is issued for execution independently of when the at least one operand is generated by the preceding instruction. Recovery circuitry is provided to perform a recovery operation in the event that the second outcome is executed for the at least one instruction and the at least one operand has not been generated by the preceding instruction when the at least one instruction is to be executed by said instruction execution circuitry.

Abstract: A data processing apparatus is described which comprises a processor operable to execute a sequence of instructions and a cache memory having a plurality of cache lines operable to store data values for access by the processor when executing the sequence of instructions. A cache controller is also provided which comprises preload circuitry operable in response to a streaming preload instruction received at the processor to store data values from a main memory into one or more cache lines of the cache memory. The cache controller also comprises identification circuitry operable in response to the streaming preload instruction to identify one or more cache lines of the cache memory for preferential reuse.

Abstract: Long undercut channels, such as a dovetail channel, are cut by electroerosion into a workpiece by a succession of electrodes each operating to provide electroerosion along the whole length of the groove rather than by an electrode passing lengthwise down the groove. The electrodes are successively advanced obliquely into the workpiece, the path of one electrode intersecting that of the other electrode or electrodes, the non-working electrodes being retracted while one of the electrodes is advanced for operation. An arrangement for simultaneously cutting two dovetail channels oppositely located on the inside of a tubular workpiece is illustrated.