Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!thunder.mcrcim.mcgill.edu!snorkelwacker.mit.edu!spool.mu.edu!think.com!zaphod.mps.ohio-state.edu!ub!uhura.cc.rochester.edu!rochester!kodak!uupsi!sunic!fuug!demos!avg From: avg@hq.demos.su (Vadim Antonov) Newsgroups: comp.arch Subject: Re: 64 bit C Message-ID: <1991Feb18.161938.26713@hq.demos.su> Date: 18 Feb 91 16:19:38 GMT References: Organization: DEMOS, Moscow, USSR Lines: 50 In marc@marc.watson.ibm.com (Marc Auslander) writes: >Anyone out there for sizeof int == 4? Novosibirsk branch of IPMCE together with DEMOS and CC of Kurchatov Institute of Atomic Energy has ported Unix v7 to 64bit machine (Elbrus-B, a successor of BESM-6). This machine occupies two cabinets: one contains 64Mb of RAM, the second contains CPU and programmable I/O channels. Benchmarks actually yield figures about 5-7 MFLOPS. Integers are represented as unnormalized floating numbers - it significantly simplifyes ALU and reduces instructions set. Like BESM-6 this machine have no microprogrammed controlling device - i.e. all instructions are implemented in hardware. Usually one word contains a pair of instructions; instructions set includes "even" and "odd" jumps. The current C implementations (one compiler was designed by Dmitry Volodin, dvv@hq.demos.su and other - by Sergey Vakulenko vak@kiae.su) support the following scheme of types: char - packed by 8 bytes per word char * - [ # of byte ] [ unused ] [ address of word ] 3 bits 27 bits int==long - [ 0000000 ] [sign] [ value ] ==short 11 bits 1 52 bits (log) unsigned int== [ 64 bits of unsigned value ] unsigned long float==double [ log ] [sign] [normalized value] 11 1 52 To have a relly short short is quite unreasonable on word-oriented machine, dereferncing of char* tooks only three operations. The port was done by a relatively small team (about 10 programmers) during a couple of years. Now they're working for porting 4.3 BSD. It can be said for sure that careful design of C-compiler practically eliminates need to make numerous changes in utilites. I was not directly involved in this project, so details probably are not precise, please ask Dmitry or Sergey for additional information. Vadim Antonov DEMOS, Moscow, USSR