| <html lang="en"> |
| <head> |
| <title>Z80 Opcodes - Using as</title> |
| <meta http-equiv="Content-Type" content="text/html"> |
| <meta name="description" content="Using as"> |
| <meta name="generator" content="makeinfo 4.13"> |
| <link title="Top" rel="start" href="index.html#Top"> |
| <link rel="up" href="Z80_002dDependent.html#Z80_002dDependent" title="Z80-Dependent"> |
| <link rel="prev" href="Z80-Directives.html#Z80-Directives" title="Z80 Directives"> |
| <link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> |
| <!-- |
| This file documents the GNU Assembler "as". |
| |
| Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, |
| 2000, 2001, 2002, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc. |
| |
| Permission is granted to copy, distribute and/or modify this document |
| under the terms of the GNU Free Documentation License, Version 1.3 |
| or any later version published by the Free Software Foundation; |
| with no Invariant Sections, with no Front-Cover Texts, and with no |
| Back-Cover Texts. A copy of the license is included in the |
| section entitled ``GNU Free Documentation License''. |
| |
| --> |
| <meta http-equiv="Content-Style-Type" content="text/css"> |
| <style type="text/css"><!-- |
| pre.display { font-family:inherit } |
| pre.format { font-family:inherit } |
| pre.smalldisplay { font-family:inherit; font-size:smaller } |
| pre.smallformat { font-family:inherit; font-size:smaller } |
| pre.smallexample { font-size:smaller } |
| pre.smalllisp { font-size:smaller } |
| span.sc { font-variant:small-caps } |
| span.roman { font-family:serif; font-weight:normal; } |
| span.sansserif { font-family:sans-serif; font-weight:normal; } |
| --></style> |
| <link rel="stylesheet" type="text/css" href="../cs.css"> |
| </head> |
| <body> |
| <div class="node"> |
| <a name="Z80-Opcodes"></a> |
| <p> |
| Previous: <a rel="previous" accesskey="p" href="Z80-Directives.html#Z80-Directives">Z80 Directives</a>, |
| Up: <a rel="up" accesskey="u" href="Z80_002dDependent.html#Z80_002dDependent">Z80-Dependent</a> |
| <hr> |
| </div> |
| |
| <h4 class="subsection">9.38.5 Opcodes</h4> |
| |
| <p>In line with common practice, Z80 mnemonics are used for both the Z80 and |
| the R800. |
| |
| <p>In many instructions it is possible to use one of the half index |
| registers (‘<samp><span class="samp">ixl</span></samp>’,‘<samp><span class="samp">ixh</span></samp>’,‘<samp><span class="samp">iyl</span></samp>’,‘<samp><span class="samp">iyh</span></samp>’) in stead of an |
| 8-bit general purpose register. This yields instructions that are |
| documented on the R800 and undocumented on the Z80. |
| Similarly <code>in f,(c)</code> is documented on the R800 and undocumented on |
| the Z80. |
| |
| <p>The assembler also supports the following undocumented Z80-instructions, |
| that have not been adopted in the R800 instruction set: |
| <dl> |
| <dt><code>out (c),0</code><dd>Sends zero to the port pointed to by register c. |
| |
| <br><dt><code>sli </code><var>m</var><dd>Equivalent to <var>m</var><code> = (</code><var>m</var><code><<1)+1</code>, the operand <var>m</var> can |
| be any operand that is valid for ‘<samp><span class="samp">sla</span></samp>’. One can use ‘<samp><span class="samp">sll</span></samp>’ as a |
| synonym for ‘<samp><span class="samp">sli</span></samp>’. |
| |
| <br><dt><var>op</var><code> (ix+</code><var>d</var><code>), </code><var>r</var><dd>This is equivalent to |
| |
| <pre class="example"> ld <var>r</var>, (ix+<var>d</var>) |
| <var>opc</var> <var>r</var> |
| ld (ix+<var>d</var>), <var>r</var> |
| </pre> |
| <p>The operation ‘<samp><var>opc</var></samp>’ may be any of ‘<samp><span class="samp">res </span><var>b</var><span class="samp">,</span></samp>’, |
| ‘<samp><span class="samp">set </span><var>b</var><span class="samp">,</span></samp>’, ‘<samp><span class="samp">rl</span></samp>’, ‘<samp><span class="samp">rlc</span></samp>’, ‘<samp><span class="samp">rr</span></samp>’, ‘<samp><span class="samp">rrc</span></samp>’, |
| ‘<samp><span class="samp">sla</span></samp>’, ‘<samp><span class="samp">sli</span></samp>’, ‘<samp><span class="samp">sra</span></samp>’ and ‘<samp><span class="samp">srl</span></samp>’, and the register |
| ‘<samp><var>r</var></samp>’ may be any of ‘<samp><span class="samp">a</span></samp>’, ‘<samp><span class="samp">b</span></samp>’, ‘<samp><span class="samp">c</span></samp>’, ‘<samp><span class="samp">d</span></samp>’, |
| ‘<samp><span class="samp">e</span></samp>’, ‘<samp><span class="samp">h</span></samp>’ and ‘<samp><span class="samp">l</span></samp>’. |
| |
| <br><dt><var>opc</var><code> (iy+</code><var>d</var><code>), </code><var>r</var><dd>As above, but with ‘<samp><span class="samp">iy</span></samp>’ instead of ‘<samp><span class="samp">ix</span></samp>’. |
| </dl> |
| |
| <p>The web site at <a href="http://www.z80.info">http://www.z80.info</a> is a good starting place to |
| find more information on programming the Z80. |
| |
| <!-- Copyright 1991, 1992, 1993, 1994, 1995, 2003 --> |
| <!-- Free Software Foundation, Inc. --> |
| <!-- This is part of the GAS manual. --> |
| <!-- For copying conditions, see the file as.texinfo. --> |
| </body></html> |
| |
