Non-Blocking API - 2022.1 English

The term non-blocking means that lack of data (or too much data) on the stream does not block the operation of a function or the iteration of a loop. Non-blocking methods return a Boolean value indicating the status of a read or write: true if successful, false otherwise. However, using non-blocking APIs can lead to non-deterministic behavior which cannot be fully validated during either C-simulation or RTL/Co-simulation, and requires an RTL testbench to test it exhaustively. Non-deterministic behavior can occur when reading from an empty FIFO or writing to a full FIFO.

During C simulation, streams have an infinite size. It is therefore not possible to validate with C simulation if the stream is full. These methods can be verified only during RTL simulation when the FIFO sizes are defined (either the default size of 1, or an arbitrary size defined with the STREAM directive).