On Sun, 03 Jun 2007 11:03:34 +0100 G T Smith <[EMAIL PROTECTED]> wrote:
> Some assembler code is truly ugly (using 100s of NOPS for timing is one > example I can think off), where timing or speed is essential one will > nearly always get a better result with well written assembler (it often > is not pretty to look at at).. Just a general comment on this since I was one of the authors of the Unix/Windows NT assembler for the Alpha chip. (This is a bit of a generalization) Alpha chip could execute multiple simultaneous streams (2 or 4 depending on the chip version), but the instructions had to be ordered properly for this to happen. We used a "scheduler" as an optimization as the last pass of the assembler. In some cases, using NOPs had a positive performance effect. Additionally, in the Intel Itanium chip, they pack 6 instructions together, and properly placed NOPs help performance. -- Jerry Feldman <[EMAIL PROTECTED]> Boston Linux and Unix user group http://www.blu.org PGP key id:C5061EA9 PGP Key fingerprint:053C 73EC 3AC1 5C44 3E14 9245 FB00 3ED5 C506 1EA9
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