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Instruction Format

A 34000 assembly language program is just a file containing a sequence of instructions and directives.

The general form of an instruction is:

label op-code operands

The label field is optional.

Line breaks in a 34000 assembler source file are significant. The operands for an instruction must appear on the same line as the op-code. A label, on the other hand, may appear on a line by itself. Such a label is associated with the first subsequent line specifying an instruction operation code. All characters on a line including and following the occurrence of a semicolon are treated as a comment to be ignored by the assembler.

The positioning of instruction components on a line is not restricted. Blanks between identifiers, constants and delimiters are ignored. In particular, labels need not be placed in the first column or followed by a colon. To allow it to distinguish labels from operation codes, the assembler treats all operation codes as reserved symbols. That is, they can not be used as labels. Case is not significant in operation codes.

A label must begin with an alphabetic character and con contain any other alphabetic or numeric characters. No special characters can be used in labels (i.e. `.', `$' and `_' are not allowed). The case of characters used in labels is significant.