Prior to v7, for the A32 encoding, this operation wrote an UNKNOWN
value back to the base register. Starting in v7 this is UNPREDICTABLE.
Reviewed-by: Peter Maydell <peter.mayd...@linaro.org>
Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
---
target/arm/translate.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/target/arm/translate.c b/target/arm/translate.c
index 3a96866531..529660eb35 100644
--- a/target/arm/translate.c
+++ b/target/arm/translate.c
@@ -9964,6 +9964,15 @@ static bool do_ldm(DisasContext *s, arg_ldst_block *a)
static bool trans_LDM_a32(DisasContext *s, arg_ldst_block *a)
{
+ /*
+ * Writeback register in register list is UNPREDICTABLE
+ * for ArchVersion() >= 7. Prior to v7, A32 would write
+ * an UNKNOWN value to the base register.
+ */
+ if (ENABLE_ARCH_7 && a->w && (a->list & (1 << a->rn))) {
+ unallocated_encoding(s);
+ return true;
+ }
return do_ldm(s, a);
}
--
2.17.1
