Re: [Patch] asm workarounds in generic header files

[David Mosberger <davidm@napali.hpl.hp.com>]

>>>>> On 09 Sep 2003 15:51:05 -0400, Jes Sorensen <jes@wildopensource.com> said:

  Jes> I actually think this is degrading the code rather then
  Jes> improving it. Right now the various macros are located in the
  Jes> include/asm-<foo> directory next to the items where they are
  Jes> used. Moving it all into one big catch-all assembly file makes
  Jes> it a lot harder to read things and debug the code. I already
  Jes> took a look at the changes that went into the ia64 part of the
  Jes> tree and I really think that was a step backwards.

In my opinion, moving all the asm-stuff greatly improved readability
of the source code.  Especially for folks who are not intimately
familiar with GCC asm syntax (which is hairy _and_ platform-specific).

  Jes> In terms of compiling the Linux kernel, I will argue that the
  Jes> Intel compiler is broken if it cannot handle inline
  Jes> assembly. Inline assembly is just too fundamental a feature for
  Jes> the kernel. This is totally ignoring the question of whether
  Jes> one should be compiling the kernel with non-GCC in the first
  Jes> place.

I think the jury is out on this one.  Clearly it's a huge benefit if
you can make do without inline asm.  GCC has to make lots of
worst-case assumptions whenever it encounters an asm statement and,
due to macros and inlining, the asm statements are not just hidden in
a few leaf routines.  In my opinion, this experiment is at least worth
a try.  If it succeeds, great, if it fails (e.g., the Intel compiler
folks fail to keep up with the kernel), all we have to do is
rm intel_intrin.h.

	--david