Re: [Qemu-devel] [PATCH] ppc: Fix xsmaddmdp and friends

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

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On Wed, Aug 21, 2019 at 10:28:41AM -0500, Paul A. Clarke wrote:
> From: "Paul A. Clarke" <pc@us.ibm.com>
> 
> A class of instructions of the form:
>   op Target,A,B
> which operate like:
>   Target = Target * A + B
> have a bit set which distinguishes them from instructions that operate as:
>   Target = Target * B + A
> 
> This bit is not being checked properly (using PPC_BIT macro), so all
> instructions in this class are operating incorrectly as the second form
> above.  The bit was being checked as if it were part of a 64-bit
> instruction opcode, rather than a proper 32-bit opcode.  Fix by using the
> macro (PPC_BIT32) which treats the opcode as a 32-bit quantity.
> 
> Signed-off-by: Paul A. Clarke <pc@us.ibm.com>

Applied to ppc-for-4.2, thanks.

> ---
>  target/ppc/translate/vsx-impl.inc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/target/ppc/translate/vsx-impl.inc.c b/target/ppc/translate/vsx-impl.inc.c
> index 3922686..8287e27 100644
> --- a/target/ppc/translate/vsx-impl.inc.c
> +++ b/target/ppc/translate/vsx-impl.inc.c
> @@ -1308,7 +1308,7 @@ static void gen_##name(DisasContext *ctx)                                     \
>      }                                                                         \
>      xt = gen_vsr_ptr(xT(ctx->opcode));                                        \
>      xa = gen_vsr_ptr(xA(ctx->opcode));                                        \
> -    if (ctx->opcode & PPC_BIT(25)) {                                          \
> +    if (ctx->opcode & PPC_BIT32(25)) {                                        \
>          /*                                                                    \
>           * AxT + B                                                            \
>           */                                                                   \

-- 
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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