target/arm: Implement MVE VHADD, VHSUB

Implement MVE VHADD and VHSUB insns, which perform an addition
or subtraction and then halve the result.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210617121628.20116-18-peter.maydell@linaro.org

1 files changed, 25 insertions, 0 deletions

diff --git a/target/arm/mve_helper.c b/target/arm/mve_helper.c
index 63eacd7349..835832fdf6 100644
--- a/target/arm/mve_helper.c
+++ b/target/arm/mve_helper.c
@@ -429,3 +429,28 @@ DO_2OP_U(vminu, DO_MIN)
 
 DO_2OP_S(vabds, DO_ABD)
 DO_2OP_U(vabdu, DO_ABD)
+
+static inline uint32_t do_vhadd_u(uint32_t n, uint32_t m)
+{
+    return ((uint64_t)n + m) >> 1;
+}
+
+static inline int32_t do_vhadd_s(int32_t n, int32_t m)
+{
+    return ((int64_t)n + m) >> 1;
+}
+
+static inline uint32_t do_vhsub_u(uint32_t n, uint32_t m)
+{
+    return ((uint64_t)n - m) >> 1;
+}
+
+static inline int32_t do_vhsub_s(int32_t n, int32_t m)
+{
+    return ((int64_t)n - m) >> 1;
+}
+
+DO_2OP_S(vhadds, do_vhadd_s)
+DO_2OP_U(vhaddu, do_vhadd_u)
+DO_2OP_S(vhsubs, do_vhsub_s)
+DO_2OP_U(vhsubu, do_vhsub_u)