Instructions, which correspond to operations the processor can executeA reserved word has a special meaning fixed by the language. You can use it only under certain conditions. MASM's reserved words include:
Instructions, which correspond to operations the processor can execute
Directives, which give commands to the assembler
Attributes, which provide a value for a field, such as segment alignment
Operators, which are used in expressions
Predefined symbols, which return information to your program
MASM reserved words are not case sensitive except for predefined symbols (see Section 1.2.3).
Summary: Use OPTION NOKEYWORD if you want to use a reserved word in another context.
The assembler generates an error if you use a reserved word as a variable, code label, or other identifier within your source code. However, if you need to use a reserved word for another purpose, the OPTION NOKEYWORD directive can selectively disable a word's status as a reserved word.
For example, to remove the STR instruction, the MASK operator, and the NAME directive from the set of words MASM recognizes as reserved, use this statement in the code segment of your program prior to the first reference to STR, MASK, or NAME:
OPTION NOKEYWORD:<STR MASK NAME>
The OPTION directive is discussed in Section 1.3.2. Appendix D provides a complete list of MASM reserved words.