5.3.4 joe Instruction

This instruction has the syntax

        joe     outcome, loc_label

and specifies control transfer to a location label loc_label if the outcome of last invoked user or mixed-type instruction is equal to outcome. The event handler of an instruction meta-class sets the number of outcomes of instructions belonging to an instruction class derived from the instruction meta-class on initialization of this instruction class.

If the assembler expects a user or mixed-type instruction at a particular location but encounters a contiguous block of joe instructions at this location, the assembler implicitly inserts a nop instruction before the contiguous block. Normally, the nop instruction does not change the outcome of last invoked instruction. After assembling the nop instruction, the assembler treats the contiguous block as a place of analysis of that outcome.