Abstract: A processor 2 is responsive to a stream of program instructions to issue program instructions under control of scheduling circuitry 6 to respective execution units 24 for execution. The execution units 24 can include error detecting circuitry 32 for detecting a change in an output signal which occurs after the output signal has latched and during an error detecting period following the latching of the output signal. The scheduling circuitry 6 is arranged so as to suppress issue of program instructions to an execution unit 24 having such error detecting circuitry 32 on consecutive processing cycles.

Abstract: An integrated circuit includes a plurality of processing stages each including processing logic 1014, a non-delayed signal-capture element 1016, a delayed signal-capture element 1018 and a comparator 1024. The non-delayed signal-capture element 1016 captures an output from the processing logic 1014 at a non-delayed capture time. At a later delayed capture time, the delayed signal-capture element 1018 also captures a value from the processing logic 1014. An error detection circuit 1026 and error correction circuit 1028 detect and correct random errors in the delayed value and supplies an error-checked delayed value to the comparator 1024. The comparator 1024 compares the error-checked delayed value and the non-delayed value and if they are not equal this indicates that the non-delayed value was captured too soon and should be replaced by the error-checked delayed value.

Abstract: A data processing system comprising a memory array having a plurality of memory cells (240-246) and read circuitry (310,320) for reading a logic value stored in one of the plurality of memory cells. The read circuitry (310,320) is operable perform two substantially simultaneous reads of the stored logic value. A voltage controller is provided and is operable to selectively vary a level of a supply voltage to the memory array. Detection circuitry is provided (330) for detecting, in dependence upon the two substantially simultaneous reads, when the supply voltage level causes the read result to be unreliable.

Abstract: An integrated circuit 2 is provided with a plurality of pipeline stages 10. These pipeline stages 10 have speculative processing control circuitry 12 which permits speculative processing in downstream pipeline stages and triggers a first error recovery operation (partial pipeline flushing) if such speculative processing is determined to be based upon an error. The pipeline stage 10 further includes speculative error detecting circuitry 14 which generates a prediction nc regarding whether or not the processing circuitry 18 will produce an error. This prediction is used to trigger a second error recovery operation (partial pipeline stall). This second error recovery operation has a lower performance penalty than the first error recovery operation.

Abstract: An instruction processing pipeline 6 is provided. This has error detection and error recovery circuitry 20 associated with one or more of the pipeline stages. If an error is detected within a signal value within that pipeline stage, then it can be repaired. Part of the error recovery may be to flush upstream program instructions from the instruction pipeline 6. When multi-threading, only those instructions from a thread including an instruction which has been lost as a consequence of the error recovery need to be flushed from the instruction pipeline 6. Instruction can also be selected for flushing in dependence upon characteristics such as privileged level, number of dependent instructions etc.

Abstract: An integrated circuit 2 includes processing pipeline stages formed of an input register 8, processing circuit 10?, 10? and an output register 12. The output register 12 employs speculative sampling and uses a subsequent speculation period during which any change in its input is detected and used to indicate a speculation error. In order to reduce the chances of a race condition giving rise to a false positive detection of a speculation error due to a too rapid signal propagation through the processing circuitry 10?, 10?, a transparent latch 14 is disposed at the approximate midpoint, measured in terms of propagation delay, within the processing circuitry 10?, 10?. This transparent latch 14 is non-transmissive during the speculation period of the output register 12 so as to prevent any new signal propagating from the input register 8 during the speculation period from reaching the output register 12.

Abstract: An integrated circuit includes a plurality of processing stages each including processing logic 1014, a non-delayed signal-capture element 1016, a delayed signal-capture element 1018 and a comparator 1024. The non-delayed signal-capture element 1016 captures an output from the processing logic 1014 at a non-delayed capture time. At a later delayed capture time, the delayed signal-capture element 1018 also captures a value from the processing logic 1014. An error detection circuit 1026 and error correction circuit 1028 detect and correct random errors in the delayed value and supplies an error-checked delayed value to the comparator 1024. The comparator 1024 compares the error-checked delayed value and the non-delayed value and if they are not equal this indicates that the non-delayed value was captured too soon and should be replaced by the error-checked delayed value.

Abstract: A memory circuit is provided comprising a memory cell, a pair of conducting lines operable to signal the logic state of the memory cell and read circuitry operable to perform a read operation by detecting a voltage level of at least one of the pair of conducting lines. The memory circuit comprises a pull-down circuit having an on configuration in which it is operable to pull-down a voltage level of at least one of the pair of conducting lines so as to affect the read operation and an off-configuration in which the pull-down circuit cannot affect the read operation. Control circuitry is provided to control whether the pull-down circuit is in the on configuration or the off configuration. The memory circuit can be incorporated in a data processing apparatus and a method of operating a memory circuit is provided in which a pull-down circuit is controlled to be in an on configuration or in an off configuration.

Abstract: A signal capture element for providing a first pre-charged logic level as first and second interim address portion signals during a pre-charged period and outputting during an evaluate period an address portion logic level as the first interim address portion signal and an inverted address portion logic level as the second interim address portion signal. First and second address portion signals are derivable respectively from first and second interim address portion signals. An inverter circuit for outputting to an address decoder during a pre-charged period a second pre-charged logic level as the first and second address portion signals. The inverter circuit having transfer characteristics that maintain voltage levels such that the first and second address portion signals are interpreted to be at the second pre-charged logic level despite the first or second interim address portion signal failing to transition to a valid logic level during the evaluate period.

Abstract: An integrated circuit 2 includes logic circuitry 10 and sequential storage elements 8. Both the logic circuit 10 and sequential storage elements 8 can be subject to particle strikes giving rise to single event upset errors. These single event upset errors can be detected by detecting a transition in the stored value stored by the sequential storage elements 8 occurring outside of a valid transition period associated with that sequential storage element 8.

Abstract: A signal interface for interfacing with an address decoder and a method of address decoding are disclosed.

Abstract: An integrated circuit includes a plurality of processing stages each including processing logic 1014, a non-delayed signal-capture element 1016, a delayed signal-capture element 1018 and a comparator 1024. The non-delayed signal-capture element 1016 captures an output from the processing logic 1014 at a non-delayed capture time. At a later delayed capture time, the delayed signal-capture element 1018 also captures a value from the processing logic 1014. An error detection circuit 1026 and error correction circuit 1028 detect and correct random errors in the delayed value and supplies an error-checked delayed value to the comparator 1024. The comparator 1024 compares the error-checked delayed value and the non-delayed value and if they are not equal this indicates that the non-delayed value was captured too soon and should be replaced by the error-checked delayed value.