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Re: [Qemu-ppc] [Qemu-devel] [PATCH] target/ppc: Fix carry flag setting f
From: |
David Gibson |
Subject: |
Re: [Qemu-ppc] [Qemu-devel] [PATCH] target/ppc: Fix carry flag setting for shift algebraic instructions |
Date: |
Tue, 3 Oct 2017 15:27:16 +1100 |
User-agent: |
Mutt/1.9.0 (2017-09-02) |
On Mon, Oct 02, 2017 at 08:19:10AM -0400, Richard Henderson wrote:
> On 09/30/2017 07:36 AM, Sandipan Das wrote:
> > For POWER ISA v3.0, the XER bit CA32 needs to be set by the shift
> > right algebraic instructions whenever the CA bit is to be set. This
> > change affects the following instructions:
> > * Shift Right Algebraic Word (sraw[.])
> > * Shift Right Algebraic Word Immediate (srawi[.])
> > * Shift Right Algebraic Doubleword (srad[.])
> > * Shift Right Algebraic Doubleword Immediate (sradi[.])
> >
> > Signed-off-by: Sandipan Das <address@hidden>
> > ---
> > target/ppc/helper.h | 4 ++--
> > target/ppc/int_helper.c | 10 ++++++++--
> > target/ppc/translate.c | 16 ++++++++++++++--
> > 3 files changed, 24 insertions(+), 6 deletions(-)
> >
> > diff --git a/target/ppc/helper.h b/target/ppc/helper.h
> > index bb6a94a8b3..069d65ad7b 100644
> > --- a/target/ppc/helper.h
> > +++ b/target/ppc/helper.h
> > @@ -40,12 +40,12 @@ DEF_HELPER_4(divwe, tl, env, tl, tl, i32)
> >
> > DEF_HELPER_FLAGS_1(popcntb, TCG_CALL_NO_RWG_SE, tl, tl)
> > DEF_HELPER_FLAGS_2(cmpb, TCG_CALL_NO_RWG_SE, tl, tl, tl)
> > -DEF_HELPER_3(sraw, tl, env, tl, tl)
> > +DEF_HELPER_4(sraw, tl, env, tl, tl, tl)
> > #if defined(TARGET_PPC64)
> > DEF_HELPER_FLAGS_2(cmpeqb, TCG_CALL_NO_RWG_SE, i32, tl, tl)
> > DEF_HELPER_FLAGS_1(popcntw, TCG_CALL_NO_RWG_SE, tl, tl)
> > DEF_HELPER_FLAGS_2(bpermd, TCG_CALL_NO_RWG_SE, i64, i64, i64)
> > -DEF_HELPER_3(srad, tl, env, tl, tl)
> > +DEF_HELPER_4(srad, tl, env, tl, tl, tl)
> > DEF_HELPER_0(darn32, tl)
> > DEF_HELPER_0(darn64, tl)
> > #endif
> > diff --git a/target/ppc/int_helper.c b/target/ppc/int_helper.c
> > index da4e1a62c9..4f270eb49d 100644
> > --- a/target/ppc/int_helper.c
> > +++ b/target/ppc/int_helper.c
> > @@ -210,7 +210,7 @@ target_ulong helper_cmpb(target_ulong rs, target_ulong
> > rb)
> >
> > /* shift right arithmetic helper */
> > target_ulong helper_sraw(CPUPPCState *env, target_ulong value,
> > - target_ulong shift)
> > + target_ulong shift, target_ulong is_isa300)
> > {
> > int32_t ret;
> >
> > @@ -231,12 +231,15 @@ target_ulong helper_sraw(CPUPPCState *env,
> > target_ulong value,
> > ret = (int32_t)value >> 31;
> > env->ca = (ret != 0);
> > }
> > + if (is_isa300) {
> > + env->ca32 = env->ca;
> > + }
>
> You do not need to pass a new parameter, because ca32 does not exist prior to
> ISA 3.00, and thus any code running ISA 2.x does not care about its value.
>
> You only need set ca32 when ca is set. Move those assignments
> adjacent.
Ah, good point.
--
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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