VAX native-mode instructions Direct assignment statements Assembler directives Instructions manipulate data. They perform such functions as addition, data conversion, and transfer of control. Instructions are usually followed in the source statement by operands, which can be any kind of data needed for the operation of the instruction. The VAX instruction set is summarized in Appendix D of this volume and is described in detail in Chapter 9 . Direct assignment statements equate symbols to values.
Assembler directives guide the assembly process and provide tools for using the instructions.
Macro directives are used to define macros and repeat blocks. Use of macros and repeat blocks helps minimize programmer errors and speeds the debugging process. A source statement can occupy one source line or can extend onto several source lines. The label field and the comment field are optional. The operand field must conform to the format of the instruction, directive, or macro specified in the operator field.