On 03/27/2011 01:45 AM, Maksym Planeta wrote: > For x86 architecture get_order function can be optimized due to > assembler instruction bsr. > > This is second version of patch where for constants gcc precompute the > result. > > Signed-off-by: Maksym Planeta <mcsim.planeta@xxxxxxxxx> gcc 4.x has an intrinsic, __builtin_clz(), which does the opposite of the bsr instruction; specifically: __builtin_clz(x) ^ 31 ... generates a bsrl instruction if x is variable. This tends to generate much better code than any assembly hacks. -hpa -- To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
