Re: [Qemu-devel] [PATCH v2] target-ppc: Fix rlwimi, rlwinm, rlwnm

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

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On Sun, Jun 19, 2016 at 03:34:35AM +1000, Anton Blanchard wrote:
> Hi rth,
> 
> > In 63ae0915f8ec, I arranged to use a 32-bit rotate, without
> > considering the effect of a mask value that wraps around to
> > the high bits of the word.
> 
> Thanks, that passes my tests.
> 
> Tested-by: Anton Blanchard <anton@samba.org>

Unfortunately the earlier buggy version already got pulled upstream.
I've folded this new version with a revert of the earlier one and
merged to ppc-for-2.7.

> 
> Anton
> 
> > Signed-off-by: Richard Henderson <rth@twiddle.net>
> > ---
> >  target-ppc/translate.c | 73
> > +++++++++++++++++++++++++++++++++++--------------- 1 file changed, 51
> > insertions(+), 22 deletions(-)
> > 
> > diff --git a/target-ppc/translate.c b/target-ppc/translate.c
> > index b689475..23bc054 100644
> > --- a/target-ppc/translate.c
> > +++ b/target-ppc/translate.c
> > @@ -1636,7 +1636,6 @@ static void gen_rlwimi(DisasContext *ctx)
> >          tcg_gen_deposit_tl(t_ra, t_ra, t_rs, sh, me - mb + 1);
> >      } else {
> >          target_ulong mask;
> > -        TCGv_i32 t0;
> >          TCGv t1;
> >  
> >  #if defined(TARGET_PPC64)
> > @@ -1645,12 +1644,21 @@ static void gen_rlwimi(DisasContext *ctx)
> >  #endif
> >          mask = MASK(mb, me);
> >  
> > -        t0 = tcg_temp_new_i32();
> >          t1 = tcg_temp_new();
> > -        tcg_gen_trunc_tl_i32(t0, t_rs);
> > -        tcg_gen_rotli_i32(t0, t0, sh);
> > -        tcg_gen_extu_i32_tl(t1, t0);
> > -        tcg_temp_free_i32(t0);
> > +        if (mask <= 0xffffffffu) {
> > +            TCGv_i32 t0 = tcg_temp_new_i32();
> > +            tcg_gen_trunc_tl_i32(t0, t_rs);
> > +            tcg_gen_rotli_i32(t0, t0, sh);
> > +            tcg_gen_extu_i32_tl(t1, t0);
> > +            tcg_temp_free_i32(t0);
> > +        } else {
> > +#if defined(TARGET_PPC64)
> > +            tcg_gen_deposit_i64(t1, t_rs, t_rs, 32, 32);
> > +            tcg_gen_rotli_i64(t1, t1, sh);
> > +#else
> > +            g_assert_not_reached();
> > +#endif
> > +        }
> >  
> >          tcg_gen_andi_tl(t1, t1, mask);
> >          tcg_gen_andi_tl(t_ra, t_ra, ~mask);
> > @@ -1678,20 +1686,28 @@ static void gen_rlwinm(DisasContext *ctx)
> >          tcg_gen_ext32u_tl(t_ra, t_rs);
> >          tcg_gen_shri_tl(t_ra, t_ra, mb);
> >      } else {
> > +        target_ulong mask;
> >  #if defined(TARGET_PPC64)
> >          mb += 32;
> >          me += 32;
> >  #endif
> > -        if (sh == 0) {
> > -            tcg_gen_andi_tl(t_ra, t_rs, MASK(mb, me));
> > -        } else {
> > -            TCGv_i32 t0 = tcg_temp_new_i32();
> > +        mask = MASK(mb, me);
> >  
> > +        if (mask <= 0xffffffffu) {
> > +            TCGv_i32 t0 = tcg_temp_new_i32();
> >              tcg_gen_trunc_tl_i32(t0, t_rs);
> >              tcg_gen_rotli_i32(t0, t0, sh);
> > -            tcg_gen_andi_i32(t0, t0, MASK(mb, me));
> > +            tcg_gen_andi_i32(t0, t0, mask);
> >              tcg_gen_extu_i32_tl(t_ra, t0);
> >              tcg_temp_free_i32(t0);
> > +        } else {
> > +#if defined(TARGET_PPC64)
> > +            tcg_gen_deposit_i64(t_ra, t_rs, t_rs, 32, 32);
> > +            tcg_gen_rotli_i64(t_ra, t_ra, sh);
> > +            tcg_gen_andi_i64(t_ra, t_ra, mask);
> > +#else
> > +            g_assert_not_reached();
> > +#endif
> >          }
> >      }
> >      if (unlikely(Rc(ctx->opcode) != 0)) {
> > @@ -1707,24 +1723,37 @@ static void gen_rlwnm(DisasContext *ctx)
> >      TCGv t_rb = cpu_gpr[rB(ctx->opcode)];
> >      uint32_t mb = MB(ctx->opcode);
> >      uint32_t me = ME(ctx->opcode);
> > -    TCGv_i32 t0, t1;
> > +    target_ulong mask;
> >  
> >  #if defined(TARGET_PPC64)
> >      mb += 32;
> >      me += 32;
> >  #endif
> > +    mask = MASK(mb, me);
> >  
> > -    t0 = tcg_temp_new_i32();
> > -    t1 = tcg_temp_new_i32();
> > -    tcg_gen_trunc_tl_i32(t0, t_rb);
> > -    tcg_gen_trunc_tl_i32(t1, t_rs);
> > -    tcg_gen_andi_i32(t0, t0, 0x1f);
> > -    tcg_gen_rotl_i32(t1, t1, t0);
> > -    tcg_temp_free_i32(t0);
> > +    if (mask <= 0xffffffffu) {
> > +        TCGv_i32 t0 = tcg_temp_new_i32();
> > +        TCGv_i32 t1 = tcg_temp_new_i32();
> > +        tcg_gen_trunc_tl_i32(t0, t_rb);
> > +        tcg_gen_trunc_tl_i32(t1, t_rs);
> > +        tcg_gen_andi_i32(t0, t0, 0x1f);
> > +        tcg_gen_rotl_i32(t1, t1, t0);
> > +        tcg_gen_extu_i32_tl(t_ra, t1);
> > +        tcg_temp_free_i32(t0);
> > +        tcg_temp_free_i32(t1);
> > +    } else {
> > +#if defined(TARGET_PPC64)
> > +        TCGv_i64 t0 = tcg_temp_new_i64();
> > +        tcg_gen_andi_i64(t0, t_rb, 0x1f);
> > +        tcg_gen_deposit_i64(t_ra, t_rs, t_rs, 32, 32);
> > +        tcg_gen_rotl_i64(t_ra, t_ra, t0);
> > +        tcg_temp_free_i64(t0);
> > +#else
> > +        g_assert_not_reached();
> > +#endif
> > +    }
> >  
> > -    tcg_gen_andi_i32(t1, t1, MASK(mb, me));
> > -    tcg_gen_extu_i32_tl(t_ra, t1);
> > -    tcg_temp_free_i32(t1);
> > +    tcg_gen_andi_tl(t_ra, t_ra, mask);
> >  
> >      if (unlikely(Rc(ctx->opcode) != 0)) {
> >          gen_set_Rc0(ctx, t_ra);
> 

-- 
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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