target/arm: Implement MVE shifts by register

Implement the MVE shifts by register, which perform
shifts on a single general-purpose register.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210628135835.6690-19-peter.maydell@linaro.org

1 files changed, 30 insertions, 0 deletions

diff --git a/target/arm/translate.c b/target/arm/translate.c
index e38619b571..28e478927d 100644
--- a/target/arm/translate.c
+++ b/target/arm/translate.c
@@ -5925,6 +5925,36 @@ static bool trans_UQSHL_ri(DisasContext *s, arg_mve_sh_ri *a)
     return do_mve_sh_ri(s, a, gen_mve_uqshl);
 }
 
+static bool do_mve_sh_rr(DisasContext *s, arg_mve_sh_rr *a, ShiftFn *fn)
+{
+    if (!arm_dc_feature(s, ARM_FEATURE_V8_1M)) {
+        /* Decode falls through to ORR/MOV UNPREDICTABLE handling */
+        return false;
+    }
+    if (!dc_isar_feature(aa32_mve, s) ||
+        !arm_dc_feature(s, ARM_FEATURE_M_MAIN) ||
+        a->rda == 13 || a->rda == 15 || a->rm == 13 || a->rm == 15 ||
+        a->rm == a->rda) {
+        /* These rda/rm cases are UNPREDICTABLE; we choose to UNDEF */
+        unallocated_encoding(s);
+        return true;
+    }
+
+    /* The helper takes care of the sign-extension of the low 8 bits of Rm */
+    fn(cpu_R[a->rda], cpu_env, cpu_R[a->rda], cpu_R[a->rm]);
+    return true;
+}
+
+static bool trans_SQRSHR_rr(DisasContext *s, arg_mve_sh_rr *a)
+{
+    return do_mve_sh_rr(s, a, gen_helper_mve_sqrshr);
+}
+
+static bool trans_UQRSHL_rr(DisasContext *s, arg_mve_sh_rr *a)
+{
+    return do_mve_sh_rr(s, a, gen_helper_mve_uqrshl);
+}
+
 /*
  * Multiply and multiply accumulate
  */