diff options
| author | Christophe Lyon <christophe.lyon@linaro.org> | 2019-10-25 11:57:11 +0200 |
|---|---|---|
| committer | Michael Roth <mdroth@linux.vnet.ibm.com> | 2019-11-04 08:34:45 -0600 |
| commit | cdc6896659b85f7ed8f7552850312e55170de0c5 (patch) | |
| tree | b67285ca6c98a905be0611cd50b1cfde44354cb6 | |
| parent | c0b35d87de345bd3b59a44c604b247a0497f2fc0 (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>
(cherry picked from commit 2529ab43b8a05534494704e803e0332d111d8b91)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
| -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 ef45cecbea..75406fd9db 100644 --- a/target/arm/translate-vfp.inc.c +++ b/target/arm/translate-vfp.inc.c @@ -704,9 +704,10 @@ 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; } } |