@ First setup a string on the heap for use as a substitution.
SSSTSSSSSN | PUSH 32 (address)
NSTTTTTTN | JSR > 11111 (spew)
@ Now prepare arguments and call printf.
SSSTSSSSSN | PUSH +32 (address)
SSSTSSSSSTN | PUSH ASCII 'A'
SSSTSTN | PUSH 5 (number of substitutions)
NSTTSSSN | JSR > 1000 (printf)