quote:Original post by d-loop
quote:Original post by Lord Bart
I compiled this on a Sun 420R server with 4 processors, 4 Gigs memory running Solairs 8 on it, using Sun 6.1 workshop ANSI C++ compiler.
Lord Bart 
I just tried your version. It's slower than the funciton I give (20%). In fact I have to rework it for intel's compiler. It don't like things like :
while(char_mask[*(++str1)]==0)
but that
while(char_mask[*(++str1)]==0)
{
}
Well not all compiler like d-loop code. for exemple VC6 don't like it (don't now about vc7.1 but I heard that MS did a good job on optimising ALU instructions).
Yeap I forgot to put the {} brackets for the while loop, sorry.
Strange it slow down on Intel.
Inc pointer and defer should be faster then asignment of defer to a char and then increment pointer.
your first loop
while(char_mask[car]==0)
{
car = (unsigned char*)*str1++; // deref, asign, inc
}
my first loop
while(char_mask[*(++str1)]==0) // inc, deref no asign.
{
}
And st3
should work out to *(st3+i) which if you replace with *(++st3) for your check should be faster since you inc the pointer instead of a pointer addition.<br><br>yours<br>while((unsigned char)st3==(unsigned char)str2)<br>{<br> i++; // extra inc of var need for defer above.<br>}<br>mine<br>while(*(++st3)==*(++st2))<br>{<br> //no need for i inc pointer instead and deref<br>}<br><br>My code keeps four things in use for main part: str1, str2, st2, st3 all of which are pointers. and are most like kept in registers.<br><br>Your code has five: car, str1, str2, st3, and i use in the main part. but it should also keep in registers, maybe, not sure on Intel box?<br><br>But I believe that compiler and processor differences matter most here. Sun processor has lots of registers, not sure how many pipelines.<br><br>Maybe I track down the gcc compiler on my box and compile it with gcc. But I won't get to it until Thurdays.<br><br>Also need to figure away I can see the asm code from the Sun compiler.<br><br>Any way it sped thing up on the Sun <img src="smile.gif" width=15 height=15 align=middle>, but slow things on Intel. <img src="sad.gif" width=15 height=15 align=middle><br><br>Well anyway nice little paper by the way. <img src="smile.gif" width=15 height=15 align=middle><br><br>Lord Bart <img src="smile.gif" width=15 height=15 align=middle> <br><br><SPAN CLASS=editedby>[edited by - lord bart on March 23, 2004 6:22:02 PM]</SPAN> <br><br><SPAN CLASS=editedby>[edited by - lord bart on March 23, 2004 6:23:22 PM]</SPAN>
