🚀 go-pugleaf

In article <505@bilver.UUCP> alex@bilver.UUCP (Alex Matulich) writes:
>Can someone help me with a puzzling problem?
>
>In my current C programming project, I have written some functions that
>perform statistical things on 400 separate data sets (linear regressions,
>standard errors, etc).  This number-crunching part takes about a minute to
>complete when I run it on my Amiga.  My Amiga uses a 68000 running at 14 MHz
>(twice the normal cpu speed) and no math chip.  The compiler is Lattice C
>4.0 in 32-bit addressing mode (similar to the IBM "large" memory model).
>
>Naturally, I wanted more speed, so I ported the program to an AT&T 386WGS
>at work, which is a 25 MHz 80386 IBM compatible.  I compiled it using
   ^^^^^^^  only creates 16-bit code....
>Turbo C 2.0, large memory model.  Then I watched in chagrined disbelief as
>that number-crunching section still took about a minute to execute --
	16-bit code on 386 can you say lame duck (read below....)
>actually a few seconds longer than my Amiga.  All source code was the same!
>
>5)  I know the 80386 has special modes of operation, incompatible with
>    previous chips, that allow it to run at its full potential.  Is this
>    the reason my program isn't running at its rightful speed?  Are these
	Yes partly, 1) 32-bit inst in real mode 2) 32-bit Protected mode
>    special modes accessible when using DOS?  If so, how?

Alex,
   the reason your program ran 'slow' on the 386 is because you compiled it
for a 286 (at best) LARGE model, a large model on a x86 means all addresses
have segment offset, haveing the x86 load segments is very 'expensive'
time wise (i normally use a small model & put large data out in far memory...)
(on a 286 or below memory accesses are restricted to 64K segments so any thing
larger then 64K (128K if you count code & data...) needs new segment) 
I don't know of any compilers (in turbo C price range) that will handle 
386 specific instructions.  Yes you can get 386 compilers but all the 
ones i know of need a 386 *nix or DOS Extenders (can you say a grand $$)
there is hope, MASM & TASM (& others...) support 386 instructions.
if you can find the 'busy' work, you could recode the busy stuff in 386
assembler (real mode) which would have a nice speed up (40% is what pkzip
claims) then the 386 'should' blow the pants off of YOUR 14mhz 68000,

    **** I AM NOT REFERING TO 680x0's IN GENERAL JUST HIS CASE!!!!! ****

the other possiblility under dos is DOS Extenders, but like i mentioned 
above the cost $$$$, ( i know my budget says NO ;-) which allow
one to write FULL 32 bit programs (nice, about the same as YOUR 32-bit
addressing mode)  A DOS Extended puts the processor in Protected mode for
your program to run, handles the interface to DOS, returns to DOS when 
your programs 'exits'.

		I hope this helps.....
			Jay
-- 
		Jay B. Harlow	<harlow@plains.nodak.edu>
	uunet!plains!harlow (UUCP)	harlow@plains (Bitnet)

Of course the above is personal opinion, And has no bearing on reality...