oldinstr_len
"\t.byte " oldinstr_len "\n" /* instruction len */ \
"\t.org . - (" oldinstr_len ") & 1\n" \
"\t.org . - (" oldinstr_len ") + (" altinstr_len(num) ")\n" \
"\t.org . - (" altinstr_len(num) ") + (" oldinstr_len ")\n"