Re: [kvm-unit-tests v2 06/10] powerpc/sprs: Specify SPRs with data rather than code

["Nicholas Piggin" <npiggin@gmail.com>]

On Thu Mar 23, 2023 at 10:36 PM AEST, Thomas Huth wrote:
> On 20/03/2023 08.03, Nicholas Piggin wrote:
> > +/* SPRs common denominator back to PowerPC Operating Environment Architecture */
> > +static const struct spr sprs_common[1024] = {
> > +  [1] = {"XER",		64,	RW,		SPR_HARNESS, }, /* Compiler */
> > +  [8] = {"LR", 		64,	RW,		SPR_HARNESS, }, /* Compiler, mfspr/mtspr */
> > +  [9] = {"CTR",		64,	RW,		SPR_HARNESS, }, /* Compiler, mfspr/mtspr */
> > + [18] = {"DSISR",	32,	OS_RW,		SPR_INT, },
> > + [19] = {"DAR",		64,	OS_RW,		SPR_INT, },
> > + [26] = {"SRR0",	64,	OS_RW,		SPR_INT, },
> > + [27] = {"SRR1",	64,	OS_RW,		SPR_INT, },
> > +[268] = {"TB",		64,	RO	,	SPR_ASYNC, },
> > +[269] = {"TBU",		32,	RO,		SPR_ASYNC, },
> > +[272] = {"SPRG0",	64,	OS_RW,		SPR_HARNESS, }, /* Int stack */
> > +[273] = {"SPRG1",	64,	OS_RW,		SPR_HARNESS, }, /* Scratch */
> > +[274] = {"SPRG2",	64,	OS_RW, },
> > +[275] = {"SPRG3",	64,	OS_RW, },
> > +[287] = {"PVR",		32,	OS_RO, },
> > +};
>
> Using a size of 1024 for each of these arrays looks weird. Why don't you add 
> a "nr" field to struct spr and specify the register number via that field 
> instead of using the index into the array as register number?

Oh I meant to reply to this. I did try it that way at first. When it
came manipulating the arrays like merging them or adding and
subtracing some SPRs, it required a bit of code to search, sort, add,
remove, etc. This way takes almost nothing. It is a dumb data structure
but it works okay here.

Thanks,
Nick