State-space Reduction in Promela model

Question

State-space Reduction: Two language statements are used to reduce the number of states in a Promela model: atomic and d-step.

Atomic is used to group statements of a particular process into one atomic sequence. The statements are executed in a single step and are not interleaved with statements of other processes. The atomicity is broken if any of the statements is blocking. That is, statements of other processes can be interleaved in between.

d-step can also be used to execute a number of statements in one step. The difference is that no intermediate states are generated or stored. If one of the statements blocks, this is considered a runtime error.