Re: [PATCH 1/1] target/arm: Allow reading flags from FPSCR for M-profile

[Peter Maydell]

On Fri, 25 Oct 2019 at 10:57, Christophe Lyon
 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 
> ---
>  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

[PATCH 1/1] target/arm: Allow reading flags from FPSCR for M-profile

[Christophe Lyon]

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 
---
 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