diff options
| author | Christophe Lyon <christophe.lyon@linaro.org> | 2019-10-25 11:57:11 +0200 |
|---|---|---|
| committer | Peter Maydell <peter.maydell@linaro.org> | 2019-11-01 20:41:00 +0000 |
| commit | 2529ab43b8a05534494704e803e0332d111d8b91 (patch) | |
| tree | f9fb9e3f6d437a42d13e116941375f5e131297e0 | |
| parent | 98be6b7d62124a1ec9a7094c2a30981f82a07f9f (diff) | |
target/arm: Allow reading flags from FPSCR for M-profile
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.
Cc: qemu-stable@nongnu.org
Signed-off-by: Christophe Lyon <christophe.lyon@linaro.org>
Message-id: 20191025095711.10853-1-christophe.lyon@linaro.org
[PMM: updated the comment]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
| -rw-r--r-- | target/arm/translate-vfp.inc.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/target/arm/translate-vfp.inc.c b/target/arm/translate-vfp.inc.c index 9ae980bef6..85c5ef897b 100644 --- a/target/arm/translate-vfp.inc.c +++ b/target/arm/translate-vfp.inc.c @@ -703,9 +703,10 @@ static bool trans_VMSR_VMRS(DisasContext *s, arg_VMSR_VMRS *a) if (arm_dc_feature(s, ARM_FEATURE_M)) { /* * The only M-profile VFP vmrs/vmsr sysreg is FPSCR. - * Writes to R15 are UNPREDICTABLE; we choose to undef. + * Accesses to R15 are UNPREDICTABLE; we choose to undef. + * (FPSCR -> r15 is a special case which writes to the PSR flags.) */ - if (a->rt == 15 || a->reg != ARM_VFP_FPSCR) { + if (a->rt == 15 && (!a->l || a->reg != ARM_VFP_FPSCR)) { return false; } } |