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* [PATCH 1/1] target/arm: Allow reading flags from FPSCR for M-profile
@ 2019-10-25  9:57 Christophe Lyon
  2019-11-01  8:38 ` Peter Maydell
  0 siblings, 1 reply; 2+ messages in thread
From: Christophe Lyon @ 2019-10-25  9:57 UTC (permalink / raw)
  To: qemu-devel; +Cc: peter.maydell, Christophe Lyon, richard.henderson

rt==15 is a special case when reading the flags: it means the
destination is APSR. This patch avoids rejecting
vmrs apsr_nzcv, fpscr
as illegal instruction.

Signed-off-by: Christophe Lyon <christophe.lyon@linaro.org>
---
 target/arm/translate-vfp.inc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/target/arm/translate-vfp.inc.c b/target/arm/translate-vfp.inc.c
index 9ae980b..82bed5b 100644
--- a/target/arm/translate-vfp.inc.c
+++ b/target/arm/translate-vfp.inc.c
@@ -705,7 +705,7 @@ static bool trans_VMSR_VMRS(DisasContext *s, arg_VMSR_VMRS *a)
          * The only M-profile VFP vmrs/vmsr sysreg is FPSCR.
          * Writes to R15 are UNPREDICTABLE; we choose to undef.
          */
-        if (a->rt == 15 || a->reg != ARM_VFP_FPSCR) {
+        if (a->rt == 15 && (!a->l || a->reg != ARM_VFP_FPSCR)) {
             return false;
         }
     }
-- 
2.7.4



^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [PATCH 1/1] target/arm: Allow reading flags from FPSCR for M-profile
  2019-10-25  9:57 [PATCH 1/1] target/arm: Allow reading flags from FPSCR for M-profile Christophe Lyon
@ 2019-11-01  8:38 ` Peter Maydell
  0 siblings, 0 replies; 2+ messages in thread
From: Peter Maydell @ 2019-11-01  8:38 UTC (permalink / raw)
  To: Christophe Lyon; +Cc: Richard Henderson, QEMU Developers

On Fri, 25 Oct 2019 at 10:57, Christophe Lyon
<christophe.lyon@linaro.org> wrote:
>
> rt==15 is a special case when reading the flags: it means the
> destination is APSR. This patch avoids rejecting
> vmrs apsr_nzcv, fpscr
> as illegal instruction.
>
> Signed-off-by: Christophe Lyon <christophe.lyon@linaro.org>
> ---
>  target/arm/translate-vfp.inc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/target/arm/translate-vfp.inc.c b/target/arm/translate-vfp.inc.c
> index 9ae980b..82bed5b 100644
> --- a/target/arm/translate-vfp.inc.c
> +++ b/target/arm/translate-vfp.inc.c
> @@ -705,7 +705,7 @@ static bool trans_VMSR_VMRS(DisasContext *s, arg_VMSR_VMRS *a)
>           * The only M-profile VFP vmrs/vmsr sysreg is FPSCR.
>           * Writes to R15 are UNPREDICTABLE; we choose to undef.
>           */
> -        if (a->rt == 15 || a->reg != ARM_VFP_FPSCR) {
> +        if (a->rt == 15 && (!a->l || a->reg != ARM_VFP_FPSCR)) {
>              return false;
>          }
>      }
> --=




Applied to target-arm.next, thanks.

-- PMM


^ permalink raw reply	[flat|nested] 2+ messages in thread

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2019-11-01  8:38 ` Peter Maydell

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