target-arm: A64: Implement PMULL instruction

Implement the PMULL instruction; this is the last unimplemented insn
in the three-reg-diff group.

Note that PMULL with size 3 is considered part of the AES part
of the crypto extensions (see the ID_AA64ISAR0_EL1 register definition
in the v8 ARM ARM), so it isn't necessary to burn an extra feature
bit on it, even though we're using more feature bits than a single
"crypto extension present/not present" toggle.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Message-id: 1394822294-14837-2-git-send-email-peter.maydell@linaro.org

1 files changed, 30 insertions, 0 deletions

diff --git a/target-arm/helper-a64.c b/target-arm/helper-a64.c
index c2ce33ee88..80ed029053 100644
--- a/target-arm/helper-a64.c
+++ b/target-arm/helper-a64.c
@@ -180,6 +180,36 @@ uint64_t HELPER(simd_tbl)(CPUARMState *env, uint64_t result, uint64_t indices,
     return result;
 }
 
+/* Helper function for 64 bit polynomial multiply case:
+ * perform PolynomialMult(op1, op2) and return either the top or
+ * bottom half of the 128 bit result.
+ */
+uint64_t HELPER(neon_pmull_64_lo)(uint64_t op1, uint64_t op2)
+{
+    int bitnum;
+    uint64_t res = 0;
+
+    for (bitnum = 0; bitnum < 64; bitnum++) {
+        if (op1 & (1ULL << bitnum)) {
+            res ^= op2 << bitnum;
+        }
+    }
+    return res;
+}
+uint64_t HELPER(neon_pmull_64_hi)(uint64_t op1, uint64_t op2)
+{
+    int bitnum;
+    uint64_t res = 0;
+
+    /* bit 0 of op1 can't influence the high 64 bits at all */
+    for (bitnum = 1; bitnum < 64; bitnum++) {
+        if (op1 & (1ULL << bitnum)) {
+            res ^= op2 >> (64 - bitnum);
+        }
+    }
+    return res;
+}
+
 /* 64bit/double versions of the neon float compare functions */
 uint64_t HELPER(neon_ceq_f64)(float64 a, float64 b, void *fpstp)
 {