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| <title>Using as: H8/300-Regs</title> |
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| Next: <a href="H8_002f300_002dAddressing.html#H8_002f300_002dAddressing" accesskey="n" rel="next">H8/300-Addressing</a>, Previous: <a href="H8_002f300_002dChars.html#H8_002f300_002dChars" accesskey="p" rel="prev">H8/300-Chars</a>, Up: <a href="H8_002f300-Syntax.html#H8_002f300-Syntax" accesskey="u" rel="up">H8/300 Syntax</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="AS-Index.html#AS-Index" title="Index" rel="index">Index</a>]</p> |
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| <a name="Register-Names-7"></a> |
| <h4 class="subsubsection">9.12.2.2 Register Names</h4> |
| |
| <a name="index-H8_002f300-registers"></a> |
| <a name="index-register-names_002c-H8_002f300"></a> |
| <p>You can use predefined symbols of the form ‘<samp>r<var>n</var>h</samp>’ and |
| ‘<samp>r<var>n</var>l</samp>’ to refer to the H8/300 registers as sixteen 8-bit |
| general-purpose registers. <var>n</var> is a digit from ‘<samp>0</samp>’ to |
| ‘<samp>7</samp>’); for instance, both ‘<samp>r0h</samp>’ and ‘<samp>r7l</samp>’ are valid |
| register names. |
| </p> |
| <p>You can also use the eight predefined symbols ‘<samp>r<var>n</var></samp>’ to refer |
| to the H8/300 registers as 16-bit registers (you must use this form for |
| addressing). |
| </p> |
| <p>On the H8/300H, you can also use the eight predefined symbols |
| ‘<samp>er<var>n</var></samp>’ (‘<samp>er0</samp>’ … ‘<samp>er7</samp>’) to refer to the 32-bit |
| general purpose registers. |
| </p> |
| <p>The two control registers are called <code>pc</code> (program counter; a |
| 16-bit register, except on the H8/300H where it is 24 bits) and |
| <code>ccr</code> (condition code register; an 8-bit register). <code>r7</code> is |
| used as the stack pointer, and can also be called <code>sp</code>. |
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