Path: utzoo!utgpu!water!watmath!clyde!rutgers!topaz.rutgers.edu!brandx.rutgers.edu!webber From: webber@brandx.rutgers.edu (Webber) Newsgroups: comp.arch Subject: machine specific languages (was: Re: C machine) Message-ID: <673@brandx.rutgers.edu> Date: 17 Dec 87 09:06:32 GMT References: <7535@alice.UUCP> Organization: Rutgers Univ., New Brunswick, N.J. Lines: 28 In article <7535@alice.UUCP>, dmr@alice.UUCP writes: > djsalomon@watdragon.waterloo.edu, in common with lots of others, > thinks that C was designed to be optimal on the PDP-11, in particular > because of the ++ and -- operators. Actually, this is much less > so than usually believed. > ... > There is in fact rather little that is PDP-11 specific in C. > Aside from things that are nearly universal these days, it prefers ... Well, it seems to me that the PDP-11 has had a major influence on subsequent architectures, so the fact that many things are nearly universal today does not contradict the notion that they are PDP-11 specific vis a vis the time when C was designed. To me, a language is machine specific when it supports exactly the set of primitive data objects that the machine supports with exactly the same set of primitive operations. (Un)fortunately, I don't have a PDP-11 instruction set handy to go down the list of which operators in PDP-11 machine code are primitives in C and which primitives in C correspond to single machine instructions, as well as which memory types can be directly declared and which declarations correspond to memory types in the architecture. Clearly the PDP-11 instruction set wasn't as restrictive as C, but C does rather nicely mirror the kinds of standard conventions that a PDP-11 assembly programmer would typically use. -------- BOB (webber@athos.rutgers.edu ; rutgers!athos.rutgers.edu!webber)