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<h5 class="subsubsection">9.18.2.2 Register Names</h5>
<p><a name="index-IA_002d64-registers-1220"></a><a name="index-register-names_002c-IA_002d64-1221"></a>
The 128 integer registers are referred to as ‘<samp><span class="samp">r</span><var>n</var></samp>’.
The 128 floating-point registers are referred to as ‘<samp><span class="samp">f</span><var>n</var></samp>’.
The 128 application registers are referred to as ‘<samp><span class="samp">ar</span><var>n</var></samp>’.
The 128 control registers are referred to as ‘<samp><span class="samp">cr</span><var>n</var></samp>’.
The 64 one-bit predicate registers are referred to as ‘<samp><span class="samp">p</span><var>n</var></samp>’.
The 8 branch registers are referred to as ‘<samp><span class="samp">b</span><var>n</var></samp>’.
In addition, the assembler defines a number of aliases:
‘<samp><span class="samp">gp</span></samp>’ (‘<samp><span class="samp">r1</span></samp>’), ‘<samp><span class="samp">sp</span></samp>’ (‘<samp><span class="samp">r12</span></samp>’), ‘<samp><span class="samp">rp</span></samp>’ (‘<samp><span class="samp">b0</span></samp>’),
‘<samp><span class="samp">ret0</span></samp>’ (‘<samp><span class="samp">r8</span></samp>’), ‘<samp><span class="samp">ret1</span></samp>’ (‘<samp><span class="samp">r9</span></samp>’), ‘<samp><span class="samp">ret2</span></samp>’ (‘<samp><span class="samp">r10</span></samp>’),
‘<samp><span class="samp">ret3</span></samp>’ (‘<samp><span class="samp">r9</span></samp>’), ‘<samp><span class="samp">farg</span><var>n</var></samp>’ (‘<samp><span class="samp">f8+</span><var>n</var></samp>’), and
‘<samp><span class="samp">fret</span><var>n</var></samp>’ (‘<samp><span class="samp">f8+</span><var>n</var></samp>’).
<p>For convenience, the assembler also defines aliases for all named application
and control registers. For example, ‘<samp><span class="samp">ar.bsp</span></samp>’ refers to the register
backing store pointer (‘<samp><span class="samp">ar17</span></samp>’). Similarly, ‘<samp><span class="samp">cr.eoi</span></samp>’ refers to
the end-of-interrupt register (‘<samp><span class="samp">cr67</span></samp>’).
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