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| <h3 class="section">3.5 Statements</h3> |
| |
| <p><a name="index-statements_002c-structure-of-130"></a><a name="index-line-separator-character-131"></a><a name="index-statement-separator-character-132"></a>A <dfn>statement</dfn> ends at a newline character (‘<samp><span class="samp">\n</span></samp>’) or line |
| separator character. (The line separator is usually ‘<samp><span class="samp">;</span></samp>’, unless this |
| conflicts with the comment character; see <a href="Machine-Dependencies.html#Machine-Dependencies">Machine Dependencies</a>.) The |
| newline or separator character is considered part of the preceding |
| statement. Newlines and separators within character constants are an |
| exception: they do not end statements. |
| |
| <p><a name="index-newline_002c-required-at-file-end-133"></a><a name="index-EOF_002c-newline-must-precede-134"></a>It is an error to end any statement with end-of-file: the last |
| character of any input file should be a newline. |
| |
| <p>An empty statement is allowed, and may include whitespace. It is ignored. |
| |
| <p><a name="index-instructions-and-directives-135"></a><a name="index-directives-and-instructions-136"></a><!-- "key symbol" is not used elsewhere in the document; seems pedantic to --> |
| <!-- @defn{} it in that case, as was done previously... doc@cygnus.com, --> |
| <!-- 13feb91. --> |
| 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 ‘<samp><span class="samp">.</span></samp>’ 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 <dfn>instruction</dfn>: it |
| assembles into a machine language instruction. |
| Different versions of <samp><span class="command">as</span></samp> for different computers |
| recognize different instructions. In fact, the same symbol may |
| represent a different instruction in a different computer's assembly |
| language. |
| |
| <p><a name="index-g_t_0040code_007b_003a_007d-_0028label_0029-137"></a><a name="index-label-_0028_0040code_007b_003a_007d_0029-138"></a>A label is a symbol immediately followed by a colon (<code>:</code>). |
| 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 <a href="Labels.html#Labels">Labels</a>. |
| |
| <p>For HPPA targets, labels need not be immediately followed by a colon, but |
| the definition of a label must begin in column zero. This also implies that |
| only one label may be defined on each line. |
| |
| <pre class="smallexample"> label: .directive followed by something |
| another_label: # This is an empty statement. |
| instruction operand_1, operand_2, ... |
| </pre> |
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