Hi Darin.

13-Apr-04 17:01:46, Darin McBride wrote to Jasen Betts


 DM> Hello Jasen!

 DM> Replying to a message of Jasen Betts to Neil Heller:

 NH>>> that I would consider it only natural that any optimizing
 NH>>> compiler would do what you did, only automatically.  Is this the
 NH>>> case?  Or should I be concerned with optimizing manually - not
 NH>>> trusting the compiler manufacturer?

 JB>> The compiler doesn't understand strlen.

 DM> ;-)  Most modern compilers probably do understand strlen.  For
 DM> example, I believe Pentiums have a single hardware instruction
 DM> that performs the strlen function much faster than software can
 DM> emulate, so you'll end up with something that looks like a
 DM> function call becoming pure assembly ;-

dunno about pentium but in 8086..

 les di,somepointer
 mov cx,0
 mov al,0
 repz scasb  ;// most of the work is done here.
 mov ax,cx

works line strlen

you can't really make it part of the compiler,
but you could make it an inline in string.h
maybe it could be part of the compier that's only active if the compuiler
reads something in string.h

 JB>> for( s=target ; *s ; s++ ) {

 DM> Yes, I like this even more ;-)

so do most compilers, pointers are faster than arrays :)

 -=> Bye <=-

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