On Thu, Jun 26, 2008 at 07:28:03AM +0100, Joel Soete wrote:
> Just for remind:
>
> Joel Soete wrote:
> >
> >
> [snip]
> >>> But this time, it seems not consider assembly:
> >>> asm volatile ("lci %%r0(%%sr1, %1), %0" : "=r" (ci) : "r"
> >>> (vba));
> >>> asm volatile ("extru %1,19,12,%0" : "+r" (ci) : "r" (ci));
> >>> asm volatile ("depw %1,15,12,%0" : "+r" (pa) : "r" (ci));
> >>>
> >>> as a 'volatile' block and insert line 1c:
>
> This seems to make better what I want:
> __asm__ __volatile__ (
> "lci %%r0(%%sr1, %2), %0\n"
> "\textru %0,19,12,%0\n"
> "\tdepw %0,15,12,%1\n"
> : "+r" (ci), "+r" (pa)
> : "r" (vba)
> : "memory"
Why the "memory"? This asm code isn't modifying memory at all.
> );
>
>
> in <ccio_map_sg>
> 200: 06 80 53 13 lci r0(sr1,r20),r19 | 200: 08 1a 02 54 copy r26,r20
> 204: d2 73 1a 74 extrw,u r19,19,12,r19 | 204: 06 a0 53 14 lci
> r0(sr1,r21),r20
> 208: 08 1a 02 5c copy r26,ret0 | 208: d2 94 1a 74 extrw,u
> r20,19,12,r20
> 20c: d7 93 0e 14 depw r19,15,12,ret0 | 20c: d7 94 0e 14 depw
> r20,15,12,ret0
> 210: 0e dc 12 80 stw ret0,0(r22) 210: 0e dc 12 80 stw ret0,0(r22)
> 214: 06 c0 12 80 fdc r0(r22) 214: 06 c0 12 80 fdc r0(r22)
> 218: 00 00 04 00 sync 218: 00 00 04 00 sync
>
> J.
>
> PS: I don't yet understand why kernel panicing when I try to get rid to
> reserve 'ci' variable and use in place a gr as r19 (even if clobbered), the
> produced object seems ok but resulting kernel panicing (even after a full
> rebuild after a make distclean???)
What's wrong with "ci" variable? It's just another register.
C compiler will allocate it and then we pass it to the asm().
And are you sure it's ok to use r19?
hth,
grant
>
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