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(nasm.info)Chapter 5

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Chapter 5: Assembler Directives
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   NASM, though it attempts to avoid the bureaucracy of assemblers like
MASM and TASM, is nevertheless forced to support a _few_ directives.
These are described in this chapter.

   NASM's directives come in two types: _user-level_ directives and
_primitive_ directives. Typically, each directive has a user-level form
and a primitive form. In almost all cases, we recommend that users use
the user-level forms of the directives, which are implemented as macros
which call the primitive forms.

   Primitive directives are enclosed in square brackets; user-level
directives are not.

   In addition to the universal directives described in this chapter,
each object file format can optionally supply extra directives in order
to control particular features of that file format. These
_format-specific_ directives are documented along with the formats that
implement them, in Note: Chapter 6.

Section 5.1

`BITS': Specifying Target Processor Mode

Section 5.2

`SECTION' or `SEGMENT': Changing and Defining Sections

Section 5.3

`ABSOLUTE': Defining Absolute Labels

Section 5.4

`EXTERN': Importing Symbols from Other Modules

Section 5.5

`GLOBAL': Exporting Symbols to Other Modules

Section 5.6

`COMMON': Defining Common Data Areas

Section 5.7

`CPU': Defining CPU Dependencies