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<H2><A NAME="SECTION009110000000000000000">
8.1.10 Nibble and Byte Swapping</A>
</H2>

<P>
Other special cases of the bit-shift operations are nibble or byte
swapping<A NAME="4207"></A>, SDCC recognizes the following
expressions:
<BLOCKQUOTE>
<TT><B>unsigned</B>&nbsp;&nbsp;char i; </TT>&nbsp;
<BR><TT><B>unsigned</B>&nbsp;&nbsp;int j; </TT>&nbsp;
<BR><TT>... </TT>&nbsp;
<BR><TT>i = ((i &lt;&lt; 4) | (i &gt;&gt;
4));</TT> 
<BR><TT>j = ((j &lt;&lt; 8) | (j &gt;&gt;
8)); </TT>

</BLOCKQUOTE>
and generates a swap instruction for the nibble swapping<A NAME="4219"></A>
or move instructions for the byte swapping<A NAME="4220"></A>.
The ''j'' example can be used to convert from little to big-endian
or vice versa. If you want to change the endianness of a <I>signed</I>
integer you have to cast to <TT>(unsigned int)</TT> first.

<P>
Note that SDCC stores numbers in little-endian<A NAME="tex2html128"
  HREF="footnode.html#foot6122"><SUP>8.1</SUP></A><A NAME="4225"></A><A NAME="4226"></A> format (i.e. lowest order
first).

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2011-03-20
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