The ASSUME directive establishes an assembly-time association between a machine register and a program object or data type. By informing the assembler of the type of information to which a register points, certain programming tasks can be simplified and the assembler can perform some operations automatically.
Syntax
ASSUME Association [, Association ...]
Association:
If the NOTHING keyword is specified for the Association field, all register associations are cancelled.
If the NOTHING keyword is specified for a particular Segment-Register or General-Purpose-Register, only the association for that register is cancelled.
The following sections describe the two types of register associations: