Date: Thu, 01 Aug 2002 09:16:08 -0400 (EDT) From: John Baldwin <jhb@FreeBSD.org> To: Mitsuru IWASAKI <iwasaki@FreeBSD.org> Cc: cvs-all@FreeBSD.org, cvs-committers@FreeBSD.org Subject: RE: cvs commit: src/sys/i386/acpica acpi_wakeup.c Message-ID: <XFMail.20020801091608.jhb@FreeBSD.org> In-Reply-To: <200208010948.g719m2DZ068561@freefall.freebsd.org>
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On 01-Aug-2002 Mitsuru IWASAKI wrote:
> iwasaki 2002/08/01 02:48:02 PDT
>
> Modified files:
> sys/i386/acpica acpi_wakeup.c
> Log:
> Fix a bug about stack manipulation at ACPI wakeup.
> This should avoid kernel panic on kernel compiled w/o
> NO_CPU_COPTFLAGS.
>
> Suggested by: optimized code by -mcpu=pentiumpro
Sorry I couldn't help you with this earlier. Thanks for fixing it!
I have a couple of questions about acpu_restorecpu():
1) Why bother moving r_eax into %eax when you zero %eax anyways
right before returning?
2) To make the code perhaps a bit easier to follow (esp. to explain
why you had to add the popl) maybe you could remove the extra
pop and change the last 3 lines to look like this:
movl ret_addr,%eax # override \n\
movl %eax,(%esp) # ret addr \n\
xorl %eax,%eax \n\
ret \n\
This also uses one less memory access although that isn't that
important. You could also use 'addl $4,%esp' instead of the pop
if you wanted.
--
John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve!" - http://www.FreeBSD.org/
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