Identifiers

Assembly identifiers are user-defined symbols representing memory locations or numbers. A symbol can contain any number of characters drawn from alphabetics, numerics, as well as special characters: dollar, $; question mark, ?; and underscore, _.

The first character of an identifier cannot be numeric nor the $ character. The case of alphabetics is significant, e.g., Fred is not the same symbol as fred. Some examples of identifiers are shown here:

An_identifier
an_identifier
an_identifier1
?$_12345

An identifier cannot be one of the assembler directives, keywords, or psect flags.

An identifier that begins with at least one underscore character can be accessed from C code. Care must be taken with such symbols that they do not interact with C code identifiers. Identifiers that do not begin with an underscore can only be accessed from the assembly domain. See Equivalent Assembly Symbols for the mapping between the C and assembly domains.