Implement Smi_bitLength intrinsic on mips, arm, and arm64.

runtime/vm/assembler_arm64.h

 // Copyright (c) 2014, 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.
 
 #ifndef VM_ASSEMBLER_ARM64_H_
 #define VM_ASSEMBLER_ARM64_H_
 
 #ifndef VM_ASSEMBLER_H_
 #error Do not include assembler_arm64.h directly; use assembler.h instead.
 #endif
@@ skipping 642 matching lines @@
   void eon(Register rd, Register rn, Operand o) {
     EmitLogicalShiftOp(EON, rd, rn, o, kDoubleWord);
   }
   void ands(Register rd, Register rn, Operand o) {
     EmitLogicalShiftOp(ANDS, rd, rn, o, kDoubleWord);
   }
   void bics(Register rd, Register rn, Operand o) {
     EmitLogicalShiftOp(BICS, rd, rn, o, kDoubleWord);
   }
 
+  // Count leading zero bits.
+  void clz(Register rd, Register rn) {
+    EmitMiscDP1Source(CLZ, rd, rn, kDoubleWord);
+  }
+
   // Misc. arithmetic.
   void udiv(Register rd, Register rn, Register rm) {
     EmitMiscDP2Source(UDIV, rd, rn, rm, kDoubleWord);
   }
   void sdiv(Register rd, Register rn, Register rm) {
     EmitMiscDP2Source(SDIV, rd, rn, rm, kDoubleWord);
   }
   void lslv(Register rd, Register rn, Register rm) {
     EmitMiscDP2Source(LSLV, rd, rn, rm, kDoubleWord);
   }
@@ skipping 1102 matching lines @@
     ASSERT((rd != R31) && (rd != CSP));
     const Register crd = ConcreteRegister(rd);
     const int32_t loimm = (imm.value() & 0x3) << 29;
     const int32_t hiimm = ((imm.value() >> 2) << kImm19Shift) & kImm19Mask;
     const int32_t encoding =
         op | loimm | hiimm |
         (static_cast<int32_t>(crd) << kRdShift);
     Emit(encoding);
   }
 
+  void EmitMiscDP1Source(MiscDP1SourceOp op,
+                         Register rd, Register rn,
+                         OperandSize sz) {
+    ASSERT((rd != CSP) && (rn != CSP));
+    ASSERT((sz == kDoubleWord) || (sz == kWord) || (sz == kUnsignedWord));
+    const Register crd = ConcreteRegister(rd);
+    const Register crn = ConcreteRegister(rn);
+    const int32_t size = (sz == kDoubleWord) ? B31 : 0;
+    const int32_t encoding =
+        op | size |
+        (static_cast<int32_t>(crd) << kRdShift) |
+        (static_cast<int32_t>(crn) << kRnShift);
+    Emit(encoding);
+  }
+
   void EmitMiscDP2Source(MiscDP2SourceOp op,
                          Register rd, Register rn, Register rm,
                          OperandSize sz) {
     ASSERT((rd != CSP) && (rn != CSP) && (rm != CSP));
     ASSERT((sz == kDoubleWord) || (sz == kWord) || (sz == kUnsignedWord));
     const Register crd = ConcreteRegister(rd);
     const Register crn = ConcreteRegister(rn);
     const Register crm = ConcreteRegister(rm);
     const int32_t size = (sz == kDoubleWord) ? B31 : 0;
     const int32_t encoding =
@@ skipping 126 matching lines @@
                                   Register value,
                                   Label* no_update);
 
   DISALLOW_ALLOCATION();
   DISALLOW_COPY_AND_ASSIGN(Assembler);
 };
 
 }  // namespace dart
 
 #endif  // VM_ASSEMBLER_ARM64_H_