Statements
==========

   A "statement" ends at a newline character (`\n') or line separator
character.  (The line separator is usually `;', unless this conflicts
with the comment character; see Machine Dependent..)  The newline
or separator character is considered part of the preceding statement.
Newlines and separators within character constants are an exception:
they don't end statements.

   It is an error to end any statement with end-of-file:  the last
character of any input file should be a newline.

   You may write a statement on more than one line if you put a
backslash (`\') immediately in front of any newlines within the
statement.  When `as' reads a backslashed newline both characters are
ignored.  You can even put backslashed newlines in the middle of symbol
names without changing the meaning of your source program.

   An empty statement is allowed, and may include whitespace.  It is
ignored.

   A statement begins with zero or more labels, optionally followed by a
key symbol which determines what kind of statement it is.  The key
symbol determines the syntax of the rest of the statement.  If the
symbol begins with a dot `.' then the statement is an assembler
directive: typically valid for any computer.  If the symbol begins with
a letter the statement is an assembly language "instruction": it will
assemble into a machine language instruction.  Different versions of
`as' for different computers will recognize different instructions.  In
fact, the same symbol may represent a different instruction in a
different computer's assembly language.

   A label is a symbol immediately followed by a colon (`:').
Whitespace before a label or after a colon is permitted, but you may not
have whitespace between a label's symbol and its colon. See Labels.

     label:     .directive    followed by something
     another_label:           # This is an empty statement.
                instruction   operand_1, operand_2, ...