Message-ID: <3469E8A5.190A@algonet.se>
Date: Wed, 12 Nov 1997 18:34:29 +0100
From: Anders Musikka <ajm AT algonet DOT se>
Reply-To: ajm AT algonet DOT se
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To: djgpp AT delorie DOT com
Subject: reply to: low level programming necesary?
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>In many ( not all ) cases assembly can be avoided by an author by writing 
>good C/C++ code, by taking short-cuts ( you don't plot every grain of sand 
>on a beach in a 3D enviroment, you plot a hundred or more per pixel, and 
>you only show the surfaces that can be seen from your point of view ) ... 
>Good C++ code may be 10,20, or 50 times slower than good assembly code, 

10,20 or 50 TIMES faster?

That's extreme! I've noticed a difference of maybe 20% for my important
inner-loops. 
(Check the asm-code a good C compiler produces, it's okay if all
optimizations are on)
Some people seem to think there's some kind of magic in
assembly ("If I write it in assembly it will be a lot faster").

There isn't!
Fast C++ code will be allmost as fast as good assembly code (maybe 10%
difference
on average).
Some people seem to think that assembly is needed to convert 
array-walks to pointer walks:

don't write: i++;x=myarray[i];
write like this instead: myarraypointer++; x=*myarraypointer;


>learn assembly ( or vice versa ).  Just don't try to learn floating point 
>in assembly, no matter what anyone says I feel it is a pain in the ass.
Hmm... it's not THAT bad on a 80386 compatible machine, is it? 
... it's like a HP pocket calculator

(fld [X]
fld [Y]
fmul
fstp [answer]
this is equivalent to: answer=X*Y)

In my oppinion Protected Mode interrupt- and exception-handling is a lot
more difficult (I've done it)