[arm] Add support for SMMLA, SMMLS and SMMUL.

src/base/bits.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/base/bits.h"
 #include "src/base/logging.h"
 
 namespace v8 {
 namespace base {
 namespace bits {
 
 uint32_t RoundUpToPowerOfTwo32(uint32_t value) {
   DCHECK_LE(value, 0x80000000u);
   value = value - 1;
   value = value | (value >> 1);
   value = value | (value >> 2);
   value = value | (value >> 4);
   value = value | (value >> 8);
   value = value | (value >> 16);
   return value + 1;
 }
 
+
+int32_t SignedMulHigh32(int32_t lhs, int32_t rhs) {
+  int64_t const value = static_cast<int64_t>(lhs) * static_cast<int64_t>(rhs);
+  return bit_cast<int32_t, uint32_t>(bit_cast<uint64_t>(value) >> 32u);
+}
+
+
+int32_t SignedMulHighAndAdd32(int32_t lhs, int32_t rhs, int32_t acc) {
+  return bit_cast<int32_t>(bit_cast<uint32_t>(acc) +
+                           bit_cast<uint32_t>(SignedMulHigh32(lhs, rhs)));
+}
+
+
+int32_t SignedMulHighAndSub32(int32_t lhs, int32_t rhs, int32_t acc) {
+  return bit_cast<int32_t>(bit_cast<uint32_t>(acc) -
+                           bit_cast<uint32_t>(SignedMulHigh32(lhs, rhs)));
+}
+
+
 }  // namespace bits
 }  // namespace base
 }  // namespace v8