Re: [Unix-jun72] status on disassembler

Tim Newsham wrote: Thanks for the thought, but I don't think it is, quite, in part because of the presence of backward branches: 2: br 1f br 2b 1: Here the 2 could be a 1, despite overlapping ranges: 1: br 1f br 1b 1: In standard register allocation, live/dead ranges are forward only: mov $0,r0 mov $1,r1 mov r0,(sp)+ mov r1,(sp)+ r0 and r1 cannot be subsumed into a single register (completely ignoring the possibility of other optimizations as off topic here). Perhaps that's merely a superficial difference, but it's enough to confuse my thinking so far, if so. To further complicate things, it would be especially nice to allocate labels not just in a legal way (that preserves the semantics of the program), but actually in a way as similar as possible to the way that humans were doing so, for the sake of improved reconstruction. (A complication with *that* is that, in some cases, the labels are obviously subtopimal, presumably due to the historical sequence of edits.) Some adaptation of e.g. graph coloring might conceivably do fine at the former but not the latter, so if I succeeded at the first I would still want to keep improving it in the direction of the second. P.S. And obviously it would yield to a big enough hammer (dynamic programming, exhaustive backtracking, genetic algorithms, simulated annealing, etc), but I dislike the idea. I'm currently pondering establishing a partial order and using a nice simple topological sort, and/or attempting a simulation of how a human might go about it -- which might end up being the simplest way to accomplish both goals. Doug -- Professional Wild-eyed Visionary Member, Crusaders for a Better Tomorrow