[comp.sys.next] RISC vs CISC yet again

dejnsen@caen.engin.umich.edu (Nik Anthony Gervae) (04/28/91)

  My architecture professor, Y N Patt, looks at the whole thing on a graph:

   |
  E|
  F|
  F| 
  I|
  C|
  I|
  E|    --->                      <---
  N|        .                  .
  C|   .                               .
  Y|
   +-------------------------------------
             COMPLEXITY
    RISC (Berkeley)                 CISC (Vax) 

   That is, early RISC chips were just as inefficient (although in
different ways) as CISC chips (CISC better at floating point math,
RISC at integer and stuff), but both are moving toward a more efficient
middle ground, using advantages learned from both schools -- sometimes
you *want* a post-increment memory access in one instruction (like the 
RS6000 I'm writing this on--marketed as "RISC"), sometimes you *want*
more simple instructions that execute in one cycle.
    My professor said exactly what Scott Hess said earlier: RISC is
good marketing these days, and little else. You say it's RISC, people
laud and buy it. The trend is more toward "HISC" (to coin an acronym):
Hybrid Instruction Set Computer......
    My NeXT is plenty fast with a 68040 (could use more than 8Meg RAM tho).
If and when NeXT or Motorola incorporate *those features of RISC* that
result in performance gains, I'll be even happier. But if they completely
buy the hype, I'll wonder just how smart they are (I'll still use their
products).

    Just my tuppence.

    Nik


--
/ Nik Gervae aka dejnsen@caen.engin.umich.edu | "It'll be finished next week, \
| CS/Linguistics stud. & NeRD at UM (go blow) | I promise!"--me               |
|                                             |                               |
| **When all else fails, bug someone who      | "Just say an iguana chewed    |
\   knows (not me!).                          | up your textbook."--Jason Fox /