The presence of a ‘ ; ’ on a line indicates the start of a comment that extends to the end of the current line. If a ‘ # ’ or ‘ * ’ appears as the first character of a line, the whole line is treated as a comment. Note that if a line starts with a ‘ # ’ character then it can also be a logical line number directive (see Comments ) or a preprocessor control command (see Preprocessing ).
Instruction, register and functional unit names are case-insensitive. as requires fully-specified functional unit names, such as ‘ .S1 ’, ‘ .L1X ’ or ‘ .D1T2 ’, on all instructions using a functional unit.
For some instructions, there may be syntactic ambiguity between register or functional unit names and the names of labels or other symbols. To avoid this, enclose the ambiguous symbol name in parentheses; register and functional unit names may not be enclosed in parentheses.