Chapter 0 MASM Reserved Words

This appendix lists the reserved words recognized by MASM. They are divided primarily by their use in the language. The primary categories are

Operands and symbols

Registers

Operators and directives

Processor instructions

Coprocessor instructions

Reserved words in MASM 6.0 are reserved under all CPU modes. Words enabled in .8086 mode, the default, can be used in all higher CPU modes. To use words from subcategories such as “Special Operands for the 80386” (Section D.1.1) requires .386 mode or higher.

You can disable the recognition of any reserved word specified in this appendix by setting the NOKEYWORD option for the OPTION directive. Once disabled, the word can be used in any way as a user-defined symbol (provided the word is a valid identifier). If you want to remove the STR instruction, the MASK operator, and the NAME directive, for instance, from the set of words MASM recognizes as reserved, add this statement to your program:

OPTION NOKEYWORD:<STR MASK NAME>

* Words in this appendix identified with an asterisk (*) are new to MASM 6.0.