5.7.4. Labels

Labels are symbols representing the addresses in memory of instructions or data. They may be program-relative, register-relative, or absolute:

Program-relative labels

These represent the program counter plus or minus a numeric constant. Use them as targets for branch instructions, or to access small items of data embedded in code areas. You can define program-relative labels using a label on an instruction or on one of the Define Constant directives. See:

Register-relative labels

These represent a named register plus a numeric constant. They are most often used to access data in data areas. You can define them with any of the Define Constant directives, the BASED Rn attribute of the AREA directive, or with a storage map. See:

Absolute addresses

These are numeric constants. They are integers in the range 0 to 232–1. They address the memory directly. The most common uses of absolute addresses are in exception handling routines and for accessing memory-mapped I/O ports.

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