A label is written as a symbol immediately followed by a colon
:
. The symbol then represents the current value of the
active location counter, and is, for example, a suitable instruction
operand. You are warned if you use the same symbol to represent two
different locations: the first definition overrides any other
definitions.
On the HPPA, the usual form for a label need not be immediately followed by a
colon, but instead must start in column zero. Only one label may be defined on
a single line. To work around this, the HPPA version of as
also
provides a special directive .label
for defining labels more flexibly.