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| <h4 class="subsection">9.34.3 PDP-11 Assembly Language Syntax</h4> |
| |
| <p><a name="index-PDP_002d11-syntax-1930"></a> |
| <a name="index-DEC-syntax-1931"></a><a name="index-BSD-syntax-1932"></a><code>as</code> supports both DEC syntax and BSD syntax. The only |
| difference is that in DEC syntax, a <code>#</code> character is used to denote |
| an immediate constants, while in BSD syntax the character for this |
| purpose is <code>$</code>. |
| |
| <p><a name="index-PDP_002d11-general_002dpurpose-register-syntax-1933"></a>general-purpose registers are named <code>r0</code> through <code>r7</code>. |
| Mnemonic alternatives for <code>r6</code> and <code>r7</code> are <code>sp</code> and |
| <code>pc</code>, respectively. |
| |
| <p><a name="index-PDP_002d11-floating_002dpoint-register-syntax-1934"></a>Floating-point registers are named <code>ac0</code> through <code>ac3</code>, or |
| alternatively <code>fr0</code> through <code>fr3</code>. |
| |
| <p><a name="index-PDP_002d11-comments-1935"></a>Comments are started with a <code>#</code> or a <code>/</code> character, and extend |
| to the end of the line. (FIXME: clash with immediates?) |
| |
| <p><a name="index-PDP_002d11-line-separator-1936"></a>Multiple statements on the same line can be separated by the ‘<samp><span class="samp">;</span></samp>’ character. |
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