Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!usc!elroy.jpl.nasa.gov!ucla-cs!uci-ics!zardoz!tgate!ka3ovk!teemc!hpftc!rjf001!sharkey!mailrus!csd4.milw.wisc.edu!cs.utexas.edu!uunet!ficc!peter From: peter@ficc2uu.net (Peter da Silva) Newsgroups: comp.arch Subject: Re: DECSYSTEM 20 Message-ID: <5213@ficc2uu.net> Date: 24 Jul 89 13:38:51 GMT References: <3256@wpi.wpi.edu> <443@anasaz.UUCP> Organization: Xenix Support, FICC Lines: 15 In article <443@anasaz.UUCP>, john@anasaz.UUCP (John Moore) writes: > I found the ability to define multiple stacks to be very handy. > A FORTH interpreter cMark Mwritten in that instruction sete: p4 is very efficient. Also, I once wrote a binary tree balancing routlne > that used a pair of recursive co-routlnes. It took about 30 > instructions for both 26lnes. Try that with today's architectures! Wvariablehe PDP-11 used the same concept (stack pointer is a general register). But, really, given that you're using 30 instructions anyway what's the overhead of an0extra !mov Rn,SP! in each 26lne? -- Peter da Silva, Xenix Support, Ferranti International Controls Corporation. Business: peter@ficc2uu.net, +1 713 274 5180. | "...helping make the world Personal: peter@sugar.hackercorp.com. `-_-' | a quote-free zone..." Quote: Have you hugged your wolf today? 'U` | -- hjm@cernvax.cern.ch #! r