Refactor bigint shifting code in preparation of shifting intrinsics.

runtime/vm/intrinsifier_arm.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"  // Needed here to get TARGET_ARCH_ARM.
 #if defined(TARGET_ARCH_ARM)
 
 #include "vm/intrinsifier.h"
 
 #include "vm/assembler.h"
@@ skipping 782 matching lines @@
   __ bic(R0, R0, Operand(kSmiTagMask));  // Remove inverted smi-tag.
   __ Ret();
 }
 
 
 void Intrinsifier::Smi_bitLength(Assembler* assembler) {
   // TODO(sra): Implement as word-length - CLZ.
 }
 
 
+void Intrinsifier::Bigint_lsh(Assembler* assembler) {
+  // TODO(regis): Implement.
+}
+
+
+void Intrinsifier::Bigint_rsh(Assembler* assembler) {
+  // TODO(regis): Implement.
+}
+
+
 void Intrinsifier::Bigint_absAdd(Assembler* assembler) {
   // static void _absAdd(Uint32List digits, int used,
   //                     Uint32List a_digits, int a_used,
   //                     Uint32List r_digits)
 
   // R2 = used, R3 = digits
   __ ldrd(R2, Address(SP, 3 * kWordSize));
   // R3 = &digits[0]
   __ add(R3, R3, Operand(TypedData::data_offset() - kHeapObjectTag));
 
@@ skipping 1141 matching lines @@
   Isolate* isolate = Isolate::Current();
   __ LoadImmediate(R1, reinterpret_cast<uword>(isolate));
   // Set return value to Isolate::current_tag_.
   __ ldr(R0, Address(R1, Isolate::current_tag_offset()));
   __ Ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM