8.34.2.2 Register Names
The assembly syntax for a register file entry is the “short” name for a TIE register file followed by the index into that register file. For example, the general-purpose AR
register file has a short name of a
, so these registers are named a0
...
a15
. As a special feature, sp
is also supported as a synonym for a1
. Additional registers may be added by processor configuration options and by designer-defined TIE extensions. An initial $ character is optional in all register names.