IBM Basic assembly language and successors: Difference between revisions

Revision as of 03:26, 9 October 2023

Revision as of 03:27, 18 October 2023

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Assembler instructions, sometimes termed [[Assembly language#Assembly directives|directives]], pseudo operations or pseudoops on other systems, are requests to the assembler to perform various operations during the code generation process. For instance, <code>CSECT</code> means "start a section of code here"; <code>DSECT</code> provides data definitions for a structure, but generates no code; <code>DC</code> defines a constant to be placed in the object code.

One of the more important assembler instructions is <code>USING</code>, which supports the truncatedbase-displacement addressing of the S/360 architecture. It guides the assembler in determining what base register and offset it should use for a relative address. In BAL, it was limited to the form

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