Abstract: A memory circuit includes an address port, a data input port and a data output port. An upstream shadow logic circuit is coupled to provide address data to the address port of the memory circuit and input data to the data input port of the memory circuit. A downstream shadow logic circuit is coupled to receive output data from the data output port of the memory circuit. The memory circuit includes a bypass path between the address port and the data output port. This bypass path is activated during a testing operation to pass bits of the address data (forming test data) applied by upstream shadow logic circuit from the address port to the data output port.

Abstract: An array of a memory includes sub-arrays with memory cells arranged in a row-column matrix where each row includes a word line and each sub-array column includes a local bit line. A row decoder supports two modes of memory operation: a first mode where only one word line in the memory array is actuated during a read and a second mode where one word line per sub-array are simultaneously actuated during the read. An input/output circuit for each column includes inputs to the local bit lines of the sub-arrays, a column data output coupled to the bit line inputs, and a sub-array data output coupled to each bit line input. BIST testing of the input/output circuit is supported through data at both the column data output and the sub-array data outputs in order to confirm proper memory operation in support of both the first and second modes of operation.

Abstract: The memory array of a memory includes sub-arrays with memory cells arranged in a row-column matrix where each row includes a word line and each sub-array column includes a local bit line. A row decoder circuit supports two modes of memory circuit operation: a first mode where only one word line in the memory array is actuated during a memory read and a second mode where one word line per sub-array are simultaneously actuated during the memory read. An input/output circuit for each column includes inputs to the local bit lines of the sub-arrays, a column data output coupled to the bit line inputs, and a sub-array data output coupled to each bit line input. Both BIST and ATPG testing of the input/output circuit are supported. For BIST testing, multiple data paths between the bit line inputs and the column data output are selectively controlled to provide complete circuit testing.

Abstract: First and second memory arrays have common word lines driven by a row decoder in response to a row address. A first word line encoder associated with the first memory array encodes signals on the word lines to generate a first encoded value, and a second word line encoder associated with the second memory array encodes signals on the word lines to generate a second encoded value. Comparison circuitry compares the first encoded value to a first expected value (e.g., a first portion of the row address) and compares the second encoded value to a second expected value (e.g., a second portion of the row address). An error flag is asserted to indicate presence of a word line fault based upon a lack of match between the first encoded value and the first expected value and/or a lack of match between the second encoded value and the second expected value.

Abstract: A failure determination circuit includes a latch circuit that receives an internal clock from a clock latch that rises in response to an external clock rising. In response to a rising edge of the external clock, the circuit generates a rising edge of a fault flag. In response to a rising edge of the internal clock if it occurs, the fault flag falls. The fault flag is then latched. The latched fault flag indicates a single bit upset in the clock latch if the falling edge of the fault flag was not generated prior to latching, if the clock latch is in an active mode, and indicates a single bit upset in the clock latch if the falling edge of the fault flag was generated prior to latching, if the clock latch is in an inactive mode.

Abstract: First and second memory arrays have common word lines driven by a row decoder in response to a row address. A first word line encoder associated with the first memory array encodes signals on the word lines to generate a first encoded value, and a second word line encoder associated with the second memory array encodes signals on the word lines to generate a second encoded value. Comparison circuitry compares the first encoded value to a first expected value (e.g., a first portion of the row address) and compares the second encoded value to a second expected value (e.g., a second portion of the row address). An error flag is asserted to indicate presence of a word line fault based upon a lack of match between the first encoded value and the first expected value and/or a lack of match between the second encoded value and the second expected value.

Abstract: A method includes monitoring a request rate of speculative memory read requests from a penultimate-level cache to a main memory. The speculative memory read requests correspond to data read requests that missed in the penultimate-level cache. A hit rate of searches of a last-level cache for data requested by the data read requests is monitored. Core demand speculative memory read requests to the main memory are selectively enabled in parallel with searching of the last-level cache for data of a corresponding core demand data read request based on the request rate and the hit rate. Prefetch speculative memory read requests to the main memory are selectively enabled in parallel with searching of the last-level cache for data of a corresponding prefetch data read request based on the request rate and the hit rate.

Abstract: A failure determination circuit includes a latch circuit that receives an internal clock from a clock latch that rises in response to an external clock rising. In response to a rising edge of the external clock, the circuit generates a rising edge of a fault flag. In response to a rising edge of the internal clock if it occurs, the fault flag falls. The fault flag is then latched. The latched fault flag indicates a single bit upset in the clock latch if the falling edge of the fault flag was not generated prior to latching, if the clock latch is in an active mode, and indicates a single bit upset in the clock latch if the falling edge of the fault flag was generated prior to latching, if the clock latch is in an inactive mode.

Abstract: A method includes monitoring a request rate of speculative memory read requests from a penultimate-level cache to a main memory. The speculative memory read requests correspond to data read requests that missed in the penultimate-level cache. A hit rate of searches of a last-level cache for data requested by the data read requests is monitored. Core demand speculative memory read requests to the main memory are selectively enabled in parallel with searching of the last-level cache for data of a corresponding core demand data read request based on the request rate and the hit rate. Prefetch speculative memory read requests to the main memory are selectively enabled in parallel with searching of the last-level cache for data of a corresponding prefetch data read request based on the request rate and the hit rate.