`.irpc SYMBOL,VALUES'...
========================
Evaluate a sequence of statements assigning different values to
SYMBOL. The sequence of statements starts at the `.irpc' directive,
and is terminated by an `.endr' directive. For each character in VALUE,
SYMBOL is set to the character, and the sequence of statements is
assembled. If no VALUE is listed, the sequence of statements is
assembled once, with SYMBOL set to the null string. To refer to SYMBOL
within the sequence of statements, use \SYMBOL.
For example, assembling
.irpc param,123
move d\param,sp@-
.endr
is equivalent to assembling
move d1,sp@-
move d2,sp@-
move d3,sp@-