Implement Smi_bitLength intrinsic on mips, arm, and arm64.

runtime/vm/intrinsifier_ia32.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.
 //
 // The intrinsic code below is executed before a method has built its frame.
 // The return address is on the stack and the arguments below it.
 // Registers EDX (arguments descriptor) and ECX (function) must be preserved.
 // Each intrinsification method returns true if the corresponding
 // Dart method was intrinsified.
 
@@ skipping 771 matching lines @@
   __ SmiUntag(EAX);  // Value.
   __ sarl(EAX, ECX);
   __ SmiTag(EAX);
   __ ret();
   __ Bind(&fall_through);
 }
 
 
 // Argument is Smi (receiver).
 void Intrinsifier::Smi_bitNegate(Assembler* assembler) {
-  __ movl(EAX, Address(ESP, + 1 * kWordSize));  // Index.
+  __ movl(EAX, Address(ESP, + 1 * kWordSize));  // Receiver.
   __ notl(EAX);
   __ andl(EAX, Immediate(~kSmiTagMask));  // Remove inverted smi-tag.
   __ ret();
 }
 
 
 void Intrinsifier::Smi_bitLength(Assembler* assembler) {
   ASSERT(kSmiTagShift == 1);
-  __ movl(EAX, Address(ESP, + 1 * kWordSize));  // Index.
+  __ movl(EAX, Address(ESP, + 1 * kWordSize));  // Receiver.
   // XOR with sign bit to complement bits if value is negative.
   __ movl(ECX, EAX);
   __ sarl(ECX, Immediate(31));  // All 0 or all 1.
   __ xorl(EAX, ECX);
   // BSR does not write the destination register if source is zero.  Put a 1 in
   // the Smi tag bit to ensure BSR writes to destination register.
   __ orl(EAX, Immediate(kSmiTagMask));
   __ bsrl(EAX, EAX);
   __ SmiTag(EAX);
   __ ret();
@@ skipping 1276 matching lines @@
                         Isolate::current_tag_offset());
   // Set return value to Isolate::current_tag_.
   __ movl(EAX, current_tag_addr);
   __ ret();
 }
 
 #undef __
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32