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From: rickert@MP.CS.NIU.EDU (Neil Rickert)
Newsgroups: comp.lang.asm370
Subject: Re: Postholes
Message-ID: <9104191903.AA25954@ucbvax.Berkeley.EDU>
Date: 19 Apr 91 17:38:38 GMT
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Reply-To: IBM 370 Assembly Programming Discussion List
              <ASM370@OHSTVMA.BITNET>
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In article <9104190111.AA00321@ucbvax.Berkeley.EDU> <phil@ux1.cso.uiuc.edu>
        writes:
>I notice that very very little assembler language programming is done on
>UNIX systems.  In part this is due to the fact that UNIX makes it easy to
>do system level functions in C and other languages.  But there is also the

  And in part this is due to the fact that the system features you would use
assembler programming on in say MVS do not even exist in Unix.  (I think
for example of the ENQ/DEQ functions for interprocess synchronization, or
the ability to create channel programs for a device not yet supported by
the operating system).

>it really is easy to do within UNIX platforms.  When developing code for
>VM/CMS or MS-DOS, for instance, you know the assembler code is going to work
>on the intended platforms anyway.  I believe it is a combination of poor
>compilers, poor run time libraries, and weak operating systems.
>
>For instance a couple years ago I was experimenting with the Mandlebrot set.
>I wrote the iteration in FORTRAN and had it optimized.  I looked at the

  When it comes to optimization, things are not always what they seem.  I
remember a few years writing the same program in Assembler, PL/I, and
FORTRAN.  I looked at the generated code for each compiler.  Like all
compiler generated code it looked pretty cruddy.  But in the innermost
loop my hand optimized assembler code had only one less instruction than
the FORTRAN code (at that time using the H-extended compiler with maximum
optimization).  The PL/I code had more than twice as many instructions in
the innermost loop.

 I also remember a few years ago talking to someone at a highly Unix oriented
company which happened to also run a large IBM/MVS shop.  I thought this
was strange, so I questionned it.  The reply was that FORTRAN was used in
their chip design software, and no Unix FORTRAN compiler came close to
matching the optimization provided by the IBM compiler.

--
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  Neil W. Rickert, Computer Science               <rickert@cs.niu.edu>
  Northern Illinois Univ.
  DeKalb, IL 60115                                   +1-815-753-6940