The -strpack=spec option performs the same
function as -string, but with two important differences. First, only the
lower seven bits from each character are stored. Pairs of 7-bit characters are then
concatenated and stored as a 14-bit word rather than in separate bytes. This is known as
string packing. This is usually only useful for devices where program space is addressed as
14-bit words (PIC10/12/16 devices). The second difference is that
-string’s t specifier is not applicable with the
-strpack option.