Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!sdd.hp.com!wuarchive!mit-eddie!bloom-beacon!eru!hagbard!sunic!kuling!rolande From: rolande@kuling.UUCP (Roland Eriksson) Newsgroups: comp.arch Subject: Re: Will NeXT survive? Grow with the times? Summary: More questions on RISC vs. CISC, Compiler design Keywords: More questions on RISC vs. CISC Message-ID: <2050@kuling.UUCP> Date: 11 May 91 16:58:52 GMT References: <11399@uwm.edu> <1991Apr29.144421.19819@oakhill.sps.mot.com> <1991Apr29.164102.11221@kithrup.COM> Reply-To: rolande@kuling.UUCP (Roland Eriksson) Organization: Dept. of Computer Systems, Uppsala University, Sweden Lines: 32 Hi! There has been a debate going on about the NeXT computer, if it will be able to keep up with the competition because of the CISC nature of the Motorola 68040. I am no expert on this subject, so please do not flame me if this posting is all wrong. IMHO the main advantage that RISC arcitechtures has over CISC is that register operations are faster than memory operations and that the compiler writer do not know good ways to use the more complex ones of the instructions of a CISC processor. This is NOW. Whe have "only" about 1 miljon transistors in the most complex processors today (RISC or CISC). But we will soon have fabrication techniques to produce chips with 10 miljon transistors. Then there will be room for (on a single chip) a really complex CISC processor (with tons of microcode), a huge amount of registers (register to register operations ARE faster), a big memory cache (with some very complex associative control logic) and maybe even some interesting "extras" (math processor with vector operations, MMU, DMA, multiple CPU:s, you name it). If this processor is built AND if compiler technology keeps up, i can *NOT* see any technical reasons why this machine will not make any RISC look like some kind of primitive *AND* slow joke. With complex instructions there will be less bus bandwidth wasted on instructions. Am i mistaken? Is compiler technology on its absolute height of evolution? Please explain this matters to me, and is there any good books on this subject? No flames please, i am no expert and i will never be one if no one tells me. Thanx, Roland. rolande@yyc.docs.uu.se