Atsushi Nemoto wrote:
> On Wed, 2 Jul 2008 10:59:56 +0100, Thiemo Seufer <ths@networkno.de> wrote:
> > > --- a/include/asm-mips/atomic.h 2008-06-25 22:38:43.159739000 -0700
> > > +++ b/include/asm-mips/atomic.h 2008-06-25 22:39:07.552065000 -0700
> > > @@ -292,10 +292,10 @@ static __inline__ int atomic_sub_if_posi
> > > " beqz %0, 2f \n"
> > > " subu %0, %1, %3 \n"
> > > " .set reorder \n"
> > > - "1: \n"
> > > " .subsection 2 \n"
> > > "2: b 1b \n"
> > > " .previous \n"
> > > + "1: \n"
> >
> > AFAICS this change should make no difference to the generated code. I
> > suspect you assembler handles .subsection incorrectly. Can you provide
> > a disassembled exapmle which gets altered by this patch? Also, please
> > tell us the exact version of the assembler you use.
>
> Why no defference? The '1b' in subsection refer backword '1' label on
> the source code (which is a label for LL insn in this case with the
> patch) ?
Oh. Now that you spelled it out I see it, too. :-)
> Anyway I can provide them. I'm using vanilla 2.17 and 2.18.
>
> Without the patch:
> 801233bc <try_acquire_console_sem>:
> 801233bc: lui v0,0x8038
> 801233c0: ll a0,31976(v0)
> 801233c4: addiu v1,a0,-1
> 801233c8: bltz v1,801233dc <try_acquire_console_sem+0x20>
> 801233cc: nop
> 801233d0: sc v1,31976(v0)
> 801233d4: beqz v1,80124dac <sys_syslog+0x8>
> 801233d8: addiu v1,a0,-1
> 801233dc: bltz v1,801233fc <try_acquire_console_sem+0x40>
> 801233e0: li v0,-1
> ...
> 80124dac: b 801233dc <try_acquire_console_sem+0x20>
> 80124db0: nop
>
> With the patch:
> 801233bc <try_acquire_console_sem>:
> 801233bc: lui v0,0x8038
> 801233c0: ll a0,31976(v0)
> 801233c4: addiu v1,a0,-1
> 801233c8: bltz v1,801233dc <try_acquire_console_sem+0x20>
> 801233cc: nop
> 801233d0: sc v1,31976(v0)
> 801233d4: beqz v1,80124dac <sys_syslog+0x8>
> 801233d8: addiu v1,a0,-1
> 801233dc: bltz v1,801233fc <try_acquire_console_sem+0x40>
> 801233e0: li v0,-1
> ...
> 80124dac: b 801233c0 <try_acquire_console_sem+0x4>
> 80124db0: nop
>
>
> The patch looks correct.
Agreed.
Thiemo
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