Re: amd64 syscall.c question

Aah, OK, that that clears it up.  I saw that the upper 32
bits went
into %edx on i386, but didn't know if anything was supposed
to
parallel this on amd64 or not.  Thanks for the clue. ;)

BTW, what is the operational distinction between
syscall_plain() and
syscall_fancy()?

Regards,

--Blair

On Wed, Jun 06, 2007 at 03:39:29PM -0400, Blair Sadewitz
wrote:

> BTW, what is the operational distinction between
syscall_plain() and
> syscall_fancy()?

Fancy handles tracing (like ktrace), plain does not. The
syscall handler is
noted in struct mdproc and entered through an indirect call.
For CPUs that
actually matter, indirect calls are more expensive than a
couple of simple
test+branch pairs, and maintaining 2x the number of syscall
paths is a pain.
So they should be merged.

Andrew