as: Preprocessing
3.1 Preprocessing
=================
The 'as' internal preprocessor:
* adjusts and removes extra whitespace. It leaves one space or tab
before the keywords on a line, and turns any other whitespace on
the line into a single space.
* removes all comments, replacing them with a single space, or an
appropriate number of newlines.
* converts character constants into the appropriate numeric values.
It does not do macro processing, include file handling, or anything
else you may get from your C compiler's preprocessor. You can do
include file processing with the '.include' directive (
(as))). You can use the GNU C compiler driver to get other "CPP"
style preprocessing by giving the input file a '.S' suffix.
Options Controlling the Kind of Output (gcc info)Overall Options.
Excess whitespace, comments, and character constants cannot be used
in the portions of the input text that are not preprocessed.
If the first line of an input file is '#NO_APP' or if you use the
'-f' option, whitespace and comments are not removed from the input
file. Within an input file, you can ask for whitespace and comment
removal in specific portions of the by putting a line that says '#APP'
before the text that may contain whitespace or comments, and putting a
line that says '#NO_APP' after this text. This feature is mainly intend
to support 'asm' statements in compilers whose output is otherwise free
of comments and whitespace.
Info Catalog
as: Syntax
as: Whitespace