  We perceive programs as single-pass instruction sequences. A single-pass
instruction sequence under execution is considered to produce a behaviour to be
controlled by some execution environment. Threads as considered in basic thread
algebra model such behaviours. We show that all regular threads, i.e. threads
that can only be in a finite number of states, can be produced by single-pass
instruction sequences without jump instructions if use can be made of Boolean
registers. We also show that, in the case where goto instructions are used
instead of jump instructions, a bound to the number of labels restricts the
expressiveness.
