##### 9.18.2.2 Register Names

The 128 integer registers are referred to as ``rn`'. The 128 floating-point registers are referred to as ``fn`'. The 128 application registers are referred to as ``arn`'. The 128 control registers are referred to as ``crn`'. The 64 one-bit predicate registers are referred to as ``pn`'. The 8 branch registers are referred to as ``bn`'. In addition, the assembler defines a number of aliases: ``gp`' (``r1`'), ``sp`' (``r12`'), ``rp`' (``b0`'), ``ret0`' (``r8`'), ``ret1`' (``r9`'), ``ret2`' (``r10`'), ``ret3`' (``r9`'), ``fargn`' (``f8+n`'), and ``fretn`' (``f8+n`').

For convenience, the assembler also defines aliases for all named application and control registers. For example, ``ar.bsp`' refers to the register backing store pointer (``ar17`'). Similarly, ``cr.eoi`' refers to the end-of-interrupt register (``cr67`').