General-purpose registers are represented by predefined symbols of the form ‘rN’, where N represents a number between
63. However, the following registers have canonical names that must be used instead:
The assembler will emit a warning if a numeric name is used instead of the non-numeric name. The
.no_require_canonical_reg_names assembler pseudo-op turns off this warning.
.require_canonical_reg_names turns it back on.