Messages in this thread | | | Date | Thu, 27 Jan 2000 18:23:00 -0500 (EST) | From | "Richard B. Johnson" <> | Subject | Re: Code optimization <LEA Instruction> |
| |
On Thu, 27 Jan 2000, Alan Cox wrote:
> > One of the things it states is that the LEA instruction can > > be used to change the value of an index register faster than > > using the ADD instruction (Page G-10, Intel '486 Rag). > > It is
It is not. Never was and can't possibly be. Further, tests show as expected, that address generation takes more time than register addition.
> > > > As usual, the Intel reference manual is wrong for all types > > of CPUs that I have tested (486-686). > > Your test is wrong. See the notes on address generation stalls >
Yea. Sure.
Cheers, Dick Johnson
Penguin : Linux version 2.3.39 on an i686 machine (800.63 BogoMips).
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
| |