Abstract: In a first aspect, a first method of injecting one or more errors in data flowing into or out of a chip is provided. The first method includes the steps of (1) generating an error injection pattern indicating one or more bits of data on which a pseudo-random error is to be inserted; and (2) generating an error injection trigger indicating when the pseudo-random error is to be inserted. Numerous other aspects are provided.

Abstract: A method and apparatus are provided for implementing speculative credit flow control in a data communications link. A receiving node selects and sends a number of speculative credits as part of a total number of credits sent to a transmitting node. The receiving node receives and processes communications from the transmitting node. The receiving node dynamically determines when a change is needed for the number of speculative credits and updates the number of speculative credits. The number of speculative credits is selected for optimizing performance on the communications link.

Abstract: An apparatus, program product and method for emulating a hardware design by time division multiplexing data communicated between an emulator and a runtime assist unit (RTAU), such as a behavior card. Data from the emulator may be received directly at the general purpose registers of the RTAU. A programmable delay may be used in conjunction with a step generator to initiate concurrent cycle processes. Code executed by the RTAU may be coded in assembly, and external interrupts that might otherwise affect the determined processing time of the RTAU task are disabled. The time multiplexing reduces card port, cabling and processing cycle requirements.

Abstract: The present invention provides for sending an envelope and replying to an envelope. A transmitter is configured to send an envelope. A receiver is coupled to the transmitter, wherein the receiver is configured to receive the envelope and generate a reply envelope. A send buffer is coupled to the transmitter. A receive buffer is coupled to the receiver. A retry timer is coupled to the transmitter, wherein the retry timer is configured to reset upon the receipt of a reply envelope correlated to the transmit envelope. The transmitter is configured to retransmit an envelope if the transmitter does not receive a corresponding reply envelope within a selected time period as determined by the retry timer. This leads to a decrease in the total number of envelopes, transmitted from both the transmitter and the receiver.