From: Christophe Lyon <christophe.l...@linaro.org>
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-sta...@nongnu.org
Signed-off-by: Christophe Lyon <christophe.l...@linaro.org>
Message-id: 20191025095711.10853-1-christophe.l...@linaro.org
[PMM: updated the comment]
Reviewed-by: Peter Maydell <peter.mayd...@linaro.org>
Signed-off-by: Peter Maydell <peter.mayd...@linaro.org>
---
target/arm/translate-vfp.inc.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/target/arm/translate-vfp.inc.c b/target/arm/translate-vfp.inc.c
index 9ae980bef63..85c5ef897be 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;
}
}
--
2.20.1
