Re: Naive Long Branch question

>>>>> On Wed, 16 Jul 2003 21:40:06 -0700 (PDT), Ravi g <[email protected]> said:

  Ravi> Hi everybody, Is Long Branch Operation supported in Linux.

Yes.

  Ravi> Ifso from which version of the kernel.

I don't remember the exact revision, but it's been there for a long time.

  Ravi> How does it support it. If i were to write directly a
  Ravi> LongBranch instruction to memory with my own compiler does the
  Ravi> Operating System have the fault handler to catch that and
  Ravi> emulate it.

On Itanium (Merced), yes.  On Itanium 2 (McKinley or Madison), the
hardware will execute it directly.

  Ravi> And in case of my own compiler who will set the 1b bit of
  Ravi> CPUID register 4,which is needed to the presence of such an
  Ravi> instruction.

You don't.  That bit is defined by hardware.  The branch-long
emulation is there for software which doesn't check that bit.

	--david