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Node:<a name="M68HC11-Branch">M68HC11-Branch</a>,

Up:<a rel="up" accesskey="u" href="M68HC11-opcodes.html#M68HC11-opcodes">M68HC11-opcodes</a>

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<h5 class="subsection">Branch Improvement</h5>



   <p>Certain pseudo opcodes are permitted for branch instructions. 

They expand to the shortest branch instruction that reach the

target. Generally these mnemonics are made by prepending <code>j</code> to

the start of Motorola mnemonic. These pseudo opcodes are not affected

by the <code>--short-branchs</code> or <code>--force-long-branchs</code> options.



   <p>The following table summarizes the pseudo-operations.



<pre class="smallexample">                                   Displacement Width

               +-------------------------------------------------------------+

               |                     Options                                 |

               |    --short-branchs            --force-long-branchs          |

               +--------------------------+----------------------------------+

     Pseudo-Op |BYTE             WORD     | BYTE          WORD               |

               +--------------------------+----------------------------------+

           bsr | bsr &lt;pc-rel&gt;    &lt;error&gt;  |               jsr &lt;abs&gt;          |

           bra | bra &lt;pc-rel&gt;    &lt;error&gt;  |               jmp &lt;abs&gt;          |

          jbsr | bsr &lt;pc-rel&gt;   jsr &lt;abs&gt; | bsr &lt;pc-rel&gt;  jsr &lt;abs&gt;          |

          jbra | bra &lt;pc-rel&gt;   jmp &lt;abs&gt; | bra &lt;pc-rel&gt;  jmp &lt;abs&gt;          |

           bXX | bXX &lt;pc-rel&gt;    &lt;error&gt;  |               bNX +3; jmp &lt;abs&gt;  |

          jbXX | bXX &lt;pc-rel&gt;   bNX +3;   | bXX &lt;pc-rel&gt;  bNX +3; jmp &lt;abs&gt;  |

               |                jmp &lt;abs&gt; |                                  |

               +--------------------------+----------------------------------+

     XX: condition

     NX: negative of condition XX

     

     </pre>



     <dl>

<dt><code>jbsr</code>

     <dd><dt><code>jbra</code>

     <dd>These are the simplest jump pseudo-operations; they always map to one

particular machine instruction, depending on the displacement to the

branch target.



     <br><dt><code>jb</code><var>XX</var><code></code>

     <dd>Here, <code>jb</code><var>XX</var><code></code> stands for an entire family of pseudo-operations,

where <var>XX</var> is a conditional branch or condition-code test.  The full

list of pseudo-ops in this family is:

     <pre class="smallexample">           jbcc   jbeq   jbge   jbgt   jbhi   jbvs   jbpl  jblo

           jbcs   jbne   jblt   jble   jbls   jbvc   jbmi

          </pre>



     <p>For the cases of non-PC relative displacements and long displacements,

<code>as</code> issues a longer code fragment in terms of

<var>NX</var>, the opposite condition to <var>XX</var>.  For example, for the

non-PC relative case:

     <pre class="smallexample">              jb<var>XX</var> foo

          </pre>

     gives

     <pre class="smallexample">               b<var>NX</var>s oof

               jmp foo

           oof:

          </pre>



   </dl>



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