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5.3 Assembler Instructions

In QSMM, there are three categories of assembler instructions: built-in instructions, user instructions, and mixed type instructions. The built-in instructions are case, casels, choice, end, jmp, joe, jprob, and stt. The assembler understands the built-in instructions without prior definition of the corresponding instruction classes and meta-classes. The built-in instructions do not necessarily induce code that is to be executed by some kind of a machine; they can be interpreted as control words that affect the structure of the machine.

User instructions are assembler instructions that have behavior specific to your application program. You declare a custom set of user instructions in an application program using corresponding instruction classes and meta-classes. You implement execution of actions associated with user instructions in event handler functions of corresponding instruction meta-classes.

Instructions abort, lookup, nop, and nop1 are ones of mixed type. The disassembler may generate instructions abort, lookup, and nop1, but assembling them requires defining the corresponding instruction classes and meta-classes. Their implementation can be specific to your application program. In certain cases, the assembler may implicitly generate nop instructions, but the assembling process will fail without the definition of the corresponding instruction class or meta-class.


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