On Wed, 2007-02-14 at 10:38 +0200, Peter wrote: > On Wed, 14 Feb 2007, Geoffrey S. Mendelson wrote: > > > On Wed, Feb 14, 2007 at 08:18:16AM +0200, Shachar Shemesh wrote: > > > >> Just for the record, it is not at all clear that, on modern CPUs, code > >> you write in machine code (or even Assembly) will, in fact, run faster. > >> The compiler can be quite good at opimizing your code for machine > >> language expression, often much better than you would be. > > > > However, a good assembly langunage programer can write code the is "leaner > > and meaner" than a compiler generates. In practical terms, a good C > > programmer can often write code that is close, and parallel processing > > CPUs where the order of instructions is critical a good compiler > > can outdo an assembly language programmer. > > HOW do you write 'lean and mean' assembly for a quad core board with AMD > or Pentium stepping (to be chosen at runtime) ? > > Peter
Small example. About two years ago I go bored, and decided to implement binary trees in (x86) Assembly. The end result was between 2-10 times faster then GCC (-O2/-O3) generated code. (Depending the size of the tree) The main reason being the lack of a 3 way comparison in C. (above/below/equal) Granted, the size of the asm code was ~10 times the comparable C code, but in certain cases it is well worth. it. BTW, certain operations (atomic operations/counters/etc) -require- asm code. - Gilboa ================================================================= To unsubscribe, send mail to [EMAIL PROTECTED] with the word "unsubscribe" in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
