Re: Which is quicker, if-else statements

As a note Turck mmcache does optimization and also caches the compiled scripts into shared memory. Zend also has the Zend Optimizer and Zend Encoder. Turck mmcache is available at http://www.turcksoft.com/en/e_mmc.htm The benchmarking I did with Turck mmcache showed that Turck was a little over 15% faster than APC for my applications (over 35,000 lines with over 25 classes). Turck comes with a nice web interface where you can disable the cache or optimizer and also view the cached scripts. Jason On Tue, 2003-03-18 at 20:38, -{ Rene Brehmer }- wrote: > On Wed, 19 Mar 2003 00:39:11 +0100, Ernest E Vogelsinger wrote about "Re: > [PHP] Which is quicker, if-else statements" what the universal translator > turned into this: > > >Noticeable? Probably not, except you're timing loops of a million or more > >cycles... but it's clear that the second method needs more time (in terms > >of cpu cycles) than the first one. > > > >In Intel speak, what would a compiler translate these code examples to? > > > >if (a == b) {} else {} > > mov eax, {a} > > cmp eax, {b} > > jnz L01 > >; the "true" block goes here > > jmp L02 > >L01: > >; the "false" (else) block goes here > >L02: > > > >As you can see there's two memory operations and one comparison. > > I'm totally lost here ... what does that mean??? > > Reminds me of assembler, except that assembler is more like: > 0001 jnp e002 e003 0005 > 0002 jmp e002 e003 0008 > > And so on (not sure if that's fully correct ... haven't touched assembler > since '92) ... > > Please ellaborate Ernest ... > > >However, PHP is _not_ a compiler, it's an interpreter. It "compiles" code > >at runtime and has not the ability to perform exhaustive optimizations > >which would cost far more time than can be gained within a single > >execution. Additionally there's the time needed to parse the input stream > >(tokenize, add to symbol table, execute token and expression parser, etc > >etc). With interpreting languages the differences will rocket skyhigh > >compared to compiled executables. > > Doesn't PHP precompile the files and shove the result into the cache? Or > did I get that wrong ??? > > Rene > > -- > Rene Brehmer > > This message was written on 100% recycled spam. > > Come see! My brand new site is now online! > http://www.metalbunny.net -- Jason Sheets <jsheets@php.net>