Re: [Qemu-devel] [PATCH 3/7] target-ppc: Implement bcds. instruction

[David Gibson <david@gibson.dropbear.id.au>]

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On Mon, Dec 05, 2016 at 02:12:29PM +1100, David Gibson wrote:
> On Sat, Dec 03, 2016 at 03:00:02AM -0200, Jose Ricardo Ziviani wrote:
> > bcds.: Decimal shift. Given two registers vra and vrb, this instruction
> > shift the vrb value by vra bits into the result register.
> > 
> > Signed-off-by: Jose Ricardo Ziviani <joserz@linux.vnet.ibm.com>
> 
> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

Sorry, I take that back...

> > ---
> >  target-ppc/helper.h                 |  1 +
> >  target-ppc/int_helper.c             | 38 +++++++++++++++++++++++++++++++++++++
> >  target-ppc/translate/vmx-impl.inc.c |  3 +++
> >  target-ppc/translate/vmx-ops.inc.c  |  3 ++-
> >  4 files changed, 44 insertions(+), 1 deletion(-)
> > 
> > diff --git a/target-ppc/helper.h b/target-ppc/helper.h
> > index bc39efb..471a1da 100644
> > --- a/target-ppc/helper.h
> > +++ b/target-ppc/helper.h
> > @@ -392,6 +392,7 @@ DEF_HELPER_3(bcdcfsq, i32, avr, avr, i32)
> >  DEF_HELPER_3(bcdctsq, i32, avr, avr, i32)
> >  DEF_HELPER_4(bcdcpsgn, i32, avr, avr, avr, i32)
> >  DEF_HELPER_3(bcdsetsgn, i32, avr, avr, i32)
> > +DEF_HELPER_4(bcds, i32, avr, avr, avr, i32)
> >  
> >  DEF_HELPER_2(xsadddp, void, env, i32)
> >  DEF_HELPER_2(xssubdp, void, env, i32)
> > diff --git a/target-ppc/int_helper.c b/target-ppc/int_helper.c
> > index 7989b1f..b25c020 100644
> > --- a/target-ppc/int_helper.c
> > +++ b/target-ppc/int_helper.c
> > @@ -3043,6 +3043,44 @@ uint32_t helper_bcdsetsgn(ppc_avr_t *r, ppc_avr_t *b, uint32_t ps)
> >      return bcd_cmp_zero(r);
> >  }
> >  
> > +uint32_t helper_bcds(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b, uint32_t ps)
> > +{
> > +    int cr;
> > +    int i = 0;
> > +    bool ox_flag = false;
> > +    int sgnb = bcd_get_sgn(b);
> > +    ppc_avr_t ret = *b;
> > +    ret.u64[LO_IDX] &= ~0xf;
> > +
> > +#if defined(HOST_WORDS_BIGENDIAN)
> > +    int upper = ARRAY_SIZE(a->s32) - 1;
> > +#else
> > +    int upper = 0;
> > +#endif
> > +
> > +    if (bcd_is_valid(b) == false) {
> > +        return CRF_SO;
> > +    }
> > +
> > +    if (a->s32[upper] > 0) {
> > +        i = (a->s32[upper] > 31) ? 31 : a->s32[upper];

Determining the shift in terms of s32 elements seems dubious when the
arch defines it in terms of byte elements.

> > +        ulshift(&ret.u64[LO_IDX], &ret.u64[HI_IDX], i * 4, &ox_flag);
> > +    } else {
> > +        i = (a->s32[upper] < -31) ? 31 : -a->s32[upper];
> > +        urshift(&ret.u64[LO_IDX], &ret.u64[HI_IDX], i * 4);
> > +    }
> > +    bcd_put_digit(&ret, bcd_preferred_sgn(sgnb, ps), 0);
> > +
> > +    *r = ret;
> > +
> > +    cr = bcd_cmp_zero(r);
> > +    if (unlikely(ox_flag)) {
> > +        cr |= CRF_SO;
> > +    }
> > +
> > +    return cr;
> > +}
> > +
> >  void helper_vsbox(ppc_avr_t *r, ppc_avr_t *a)
> >  {
> >      int i;
> > diff --git a/target-ppc/translate/vmx-impl.inc.c b/target-ppc/translate/vmx-impl.inc.c
> > index e8e527f..84ebb7e 100644
> > --- a/target-ppc/translate/vmx-impl.inc.c
> > +++ b/target-ppc/translate/vmx-impl.inc.c
> > @@ -1016,6 +1016,7 @@ GEN_BCD2(bcdcfsq)
> >  GEN_BCD2(bcdctsq)
> >  GEN_BCD2(bcdsetsgn)
> >  GEN_BCD(bcdcpsgn);
> > +GEN_BCD(bcds);
> >  
> >  static void gen_xpnd04_1(DisasContext *ctx)
> >  {
> > @@ -1090,6 +1091,8 @@ GEN_VXFORM_DUAL(vsubuhs, PPC_ALTIVEC, PPC_NONE, \
> >                  bcdsub, PPC_NONE, PPC2_ALTIVEC_207)
> >  GEN_VXFORM_DUAL(vaddshs, PPC_ALTIVEC, PPC_NONE, \
> >                  bcdcpsgn, PPC_NONE, PPC2_ISA300)
> > +GEN_VXFORM_DUAL(vsubudm, PPC2_ALTIVEC_207, PPC_NONE, \
> > +                bcds, PPC_NONE, PPC2_ISA300)
> >  
> >  static void gen_vsbox(DisasContext *ctx)
> >  {
> > diff --git a/target-ppc/translate/vmx-ops.inc.c b/target-ppc/translate/vmx-ops.inc.c
> > index 57dce6e..7b4b009 100644
> > --- a/target-ppc/translate/vmx-ops.inc.c
> > +++ b/target-ppc/translate/vmx-ops.inc.c
> > @@ -62,7 +62,8 @@ GEN_VXFORM_207(vaddudm, 0, 3),
> >  GEN_VXFORM_DUAL(vsububm, bcdadd, 0, 16, PPC_ALTIVEC, PPC_NONE),
> >  GEN_VXFORM_DUAL(vsubuhm, bcdsub, 0, 17, PPC_ALTIVEC, PPC_NONE),
> >  GEN_VXFORM(vsubuwm, 0, 18),
> > -GEN_VXFORM_207(vsubudm, 0, 19),
> > +GEN_VXFORM_DUAL(vsubudm, bcds, 0, 19, PPC2_ALTIVEC_207, PPC2_ISA300),
> > +GEN_VXFORM_300(bcds, 0, 27),
> >  GEN_VXFORM(vmaxub, 1, 0),
> >  GEN_VXFORM(vmaxuh, 1, 1),
> >  GEN_VXFORM(vmaxuw, 1, 2),
> 



-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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