HLASM: V1R6 Language Ref

Assembler language structureOverview of assembler language structure┌─────────────────────────┐│││ Source module ││ made up of ││ source statements │││└────────────┬────────────┘│ Which can be│EITHER │ OR┌──────────────────────────◄─┴─►──────────────────────────┐┌────────────┴────────────┐┌────────────┴────────────┐│ │ │ ││ INSTRUCTION │ │ COMMENT ││ STATEMENTS │ │ STATEMENTS ││ │ │ │└────────────┬────────────┘└────────────┬────────────┘││ Which are of ││ three main types │┌─────────────────────┼─────────────────────┐│ │┌───────┴───────┐ ┌───────┴───────┐ ┌───────┴───────┐ ││ MACHINE │ │ ASSEMBLER │ │ MACRO │ ││ Instructions │ │ Instructions │ │ Instructions │ │└───────┬───────┘ └───────┬───────┘ └───────┬───────┘ │ │└─────────────────────┼─────────────────────┘│││ Which are composed of ││ from one to four fields │┌─────────────────────┼─────────────────────┬─────────────────────┐│ │┌───────┴───────┐ ┌───────┴───────┐ ┌───────┴───────┐ ┌───────┴───────┐ ││ NAME │ │ OPERATION │ │ OPERAND │ │ REMARKS │ │└───────┬───────┘ └───────┬───────┘ └───────┬───────┘ └───────┬───────┘ │ │┌───────┴───────┐ ┌───────┴───────┐ │ └───────────►─┤│ No DBCS │ │ No DBCS │ Which, for machine │└───────────────┘ └───────────────┘ │ instructions, is ││ composed of │┌───────┴───────┐││ EXPRESSIONS │ │└───────┬───────┘│││ Which are ││ composed of │┌──────────┴──────────┐ Which are │ composed of┌───────┴───────┐ ┌───────┴───────┐ ┌───────┴───────┐│ TERMS │ │ Combination │ │ Any ││ │ │ of terms │ │ Characters │└───────┬───────┘ └───────┬───────┘ └───────┬───────┘ └─────────────────────┼────────────────────────┘│ Which are│ composed of┌─────────┴─────────┐│ EBCDIC and DBCS ││ CHARACTERS │└───────────────────┘Figure 3. Overview of assembler language structure22 HLASM: V1R6 Language Ref