Re: [Linux-ia64] unalinged access by loadpair instruction

2002-12-10T12:18:55Z

Hi David,

Indeed, you are right. There is my mistake in my program.
The register will be overwritten...

Thank you.

End of my email
--
Yours faithfully,
Hideki Yamamoto (V).v.(V) # Empowered by Innovation

> > The core-loop isn't right because br.ctop renames by one register
> > position, not two. I attached a version of the test program which
> > does what you wanted.
> Sorry, I did not understand why my program is buggy
> even if I saw your program. So the incremental value
> in my program is 8bytes, it means on purpose. :-)
>
> Thanks you for sending the patch.
>
> End of my email
> --
> Yours faithfully,
> Hideki Yamamoto (V).v.(V) # Empowered by Innovation
>
> >
> > === arch/ia64/kernel/unaligned.c 1.6 vs edited ==> > --- 1.6/arch/ia64/kernel/unaligned.c Thu Mar 14 00:28:41 2002
> > +++ edited/arch/ia64/kernel/unaligned.c Mon Dec 9 18:24:54 2002
> > @@ -486,7 +486,21 @@
> > DPRINT("*0x%lx=0x%lx NaT=%d new unat: %p=%lx\n", addr, val, nat, (void *) unat,*unat);
> > }
> >
> > -#define IA64_FPH_OFFS(r) (r - IA64_FIRST_ROTATING_FR)
> > +/*
> > + * Return the (rotated) index for floating point register REGNUM (REGNUM must be in the
> > + * range from 32-127, result is in the range from 0-95.
> > + */
> > +static inline unsigned long
> > +fph_index (struct pt_regs *regs, long regnum)
> > +{
> > + unsigned long rrb_fr = (regs->cr_ifs >> 25) & 0x7f;
> > +
> > + regnum -= IA64_FIRST_ROTATING_FR;
> > + regnum += rrb_fr;
> > + if (regnum >= 96)
> > + regnum -= 96;
> > + return regnum;
> > +}
> >
> > static void
> > setfpreg (unsigned long regnum, struct ia64_fpreg *fpval, struct pt_regs *regs)
> > @@ -507,7 +521,7 @@
> > */
> > if (regnum >= IA64_FIRST_ROTATING_FR) {
> > ia64_sync_fph(current);
> > - current->thread.fph[IA64_FPH_OFFS(regnum)] = *fpval;
> > + current->thread.fph[fph_index(regs, regnum)] = *fpval;
> > } else {
> > /*
> > * pt_regs or switch_stack ?
> > @@ -566,7 +580,7 @@
> > */
> > if (regnum >= IA64_FIRST_ROTATING_FR) {
> > ia64_flush_fph(current);
> > - *fpval = current->thread.fph[IA64_FPH_OFFS(regnum)];
> > + *fpval = current->thread.fph[fph_index(regs, regnum)];
> > } else {
> > /*
> > * f0 = 0.0, f1= 1.0. Those registers are constant and are thus
> > ----------------------------------------------------
> > #define n 100
> >
> > double d[n],d2[n+1];
> >
> > main() {
> > int i,j;
> >
> > for (i = 0; i < n; i++) {
> > d[i] = i;
> > d2[i] = 0.0;
> > }
> > copy_by_loadpair(&d, &d2, n/2-1);
> > for (i = 0; i < n; i++) {
> > if (d2[i] != i)
> > printf("d2[%d] = %f, should be d[%d]=%f\n",
> > i, d2[i], i, d[i]);
> > }
> > }
> >
> > ----------------------------------------------------
> > .file "a.c"
> > .pred.safe_across_calls p1-p5,p16-p63
> > .text
> > .align 16
> > .global copy_by_loadpair
> > .proc copy_by_loadpair
> > copy_by_loadpair:
> > alloc r8=ar.pfs,3,6,0,0 ;;
> > mov r15=r32
> > mov r2=r33
> > add r3=8,r33
> > mov ar.lc=r34
> > mov pr.rot=0x10000
> > mov ar.ec=5 ;;
> > L1:
> > (p16) ldfpd f32,f37=[r15],16
> > (p20) stfd [r2]ó6,16
> > (p20) stfd [r3]ô1,16
> > br.ctop.sptk L1;;
> > br.ret.sptk.many b0 ;;
> > .endp get_by_loadpair
> >
> > _______________________________________________
> > Linux-IA64 mailing list
> > Linux-IA64@linuxia64.org
> > http://lists.linuxia64.org/lists/listinfo/linux-ia64
> >
>
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