Process two 32-bit digits as one 64-bit digit in all bigint intrinsics on ARM64.

runtime/vm/assembler_arm64_test.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_ARM64)
 
 #include "vm/assembler.h"
 #include "vm/cpu.h"
 #include "vm/os.h"
@@ skipping 1431 matching lines @@
   __ ret();
 }
 
 
 ASSEMBLER_TEST_RUN(Smulh_neg, test) {
   typedef int64_t (*Int64Return)() DART_UNUSED;
   EXPECT_EQ(-1, EXECUTE_TEST_CODE_INT64(Int64Return, test->entry()));
 }
 
 
+ASSEMBLER_TEST_GENERATE(Umulh, assembler) {
+  __ movz(R1, Immediate(-1), 3);  // 0xffff000000000000
+  __ movz(R2, Immediate(7), 3);  // 0x0007000000000000
+  __ umulh(R0, R1, R2);  // 0x0006fff900000000
+  __ ret();
+}
+
+
+ASSEMBLER_TEST_RUN(Umulh, test) {
+  typedef int64_t (*Int64Return)() DART_UNUSED;
+  EXPECT_EQ(static_cast<int64_t>(0x6fff900000000),
+            EXECUTE_TEST_CODE_INT64(Int64Return, test->entry()));
+}
+
+
 ASSEMBLER_TEST_GENERATE(Umaddl, assembler) {
   __ movn(R1, Immediate(0), 0);  // W1 = 0xffffffff.
   __ movz(R2, Immediate(7), 0);  // W2 = 7.
   __ movz(R3, Immediate(8), 0);  // X3 = 8.
   __ umaddl(R0, R1, R2, R3);  // X0 = W1*W2 + X3 = 0x700000001.
   __ ret();
 }
 
 
 ASSEMBLER_TEST_RUN(Umaddl, test) {
@@ skipping 2118 matching lines @@
 
   EXPECT_EQ(-1, RANGE_OF(Bool::True().raw()));
 
 #undef RANGE_OF
 }
 
 
 }  // namespace dart
 
 #endif  // defined(TARGET_ARCH_ARM64)