There are two ways of rendering comments to the assembler. In both cases the comment is equivalent to one space.
Anything from “/*” through the next “*/” is a comment. This means you may not nest these comments.
/*
The only way to include a newline ('\n') in a comment
is to use this sort of comment.
*/
/* This sort of comment does not nest. */
Anything from the line comment character to the next newline is considered a comment and is ignored. The line comment character is see Chapter 30.
On some machines there are two different line comment characters. One character only begins a comment if it is the first non-white-space character on a line, while the other always begins a comment.
To be compatible with past assemblers, lines that begin with “#” have a special interpretation. Following the “#” should be an absolute expression (see Chapter 28.): the logical line number of the next line. Then a string (see Section 25.6.1.1.) is allowed: if present it is a new logical file name. The rest of the line, if any, should be white-space.
If the first non-white-space characters on the line are not numeric, the line is ignored. (Just like a comment.)
# This is an ordinary comment.
# 42-6 "new_file_name" # New logical file name
# This is logical line # 36.
This feature is deprecated, and may disappear from future versions of the assembler.