target/arm: Implement the ADDG, SUBG instructions

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200626033144.790098-12-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 10 insertions, 0 deletions

diff --git a/target/arm/mte_helper.c b/target/arm/mte_helper.c
index 539a04de84..9ab9ed749d 100644
--- a/target/arm/mte_helper.c
+++ b/target/arm/mte_helper.c
@@ -70,3 +70,13 @@ uint64_t HELPER(irg)(CPUARMState *env, uint64_t rn, uint64_t rm)
 
     return address_with_allocation_tag(rn, rtag);
 }
+
+uint64_t HELPER(addsubg)(CPUARMState *env, uint64_t ptr,
+                         int32_t offset, uint32_t tag_offset)
+{
+    int start_tag = allocation_tag_from_addr(ptr);
+    uint16_t exclude = extract32(env->cp15.gcr_el1, 0, 16);
+    int rtag = choose_nonexcluded_tag(start_tag, tag_offset, exclude);
+
+    return address_with_allocation_tag(ptr + offset, rtag);
+}