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) ?
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.
---
Atsushi Nemoto
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