All, I'm trying to write a PDP-11 disassembler for a.out files. I'm having trouble dealing with jsrs. Take, for example, the code here: http://minnie.tuhs.org/UnixTree/1972_stuff/s1/frag19.html I can happily deal with the jsr pc,do type of jsr, but the ones involving r5 have me stumped, e.g.: jsr r5,questf; < nonexistent\n\0>; .even It appears that data is being inserted into the executable directly after the jsr instruction. How does the rts which returns from the jsr know how much data to skip, and what is the involvement of r5 here? Thanks, Warren