Process a pair of registers in one instruction where possible on arm in the VM.

runtime/vm/stub_code_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"
 #if defined(TARGET_ARCH_ARM)
 
 #include "vm/assembler.h"
 #include "vm/code_generator.h"
 #include "vm/cpu.h"
@@ skipping 1736 matching lines @@
   __ EnterStubFrame();
   __ CallRuntime(kSingleStepHandlerRuntimeEntry, 0);
   __ LeaveStubFrame();
   __ b(&done_stepping);
 }
 
 
 // Used to check class and type arguments. Arguments passed in registers:
 // LR: return address.
 // R0: instance (must be preserved).
-// R1: instantiator type arguments (only if n == 4, can be raw_null).
-// R2: function type arguments (only if n == 4, can be raw_null).
+// R2: instantiator type arguments (only if n == 4, can be raw_null).
+// R1: function type arguments (only if n == 4, can be raw_null).
 // R3: SubtypeTestCache.
 // Result in R1: null -> not found, otherwise result (true or false).
 static void GenerateSubtypeNTestCacheStub(Assembler* assembler, int n) {
   ASSERT((n == 1) || (n == 2) || (n == 4));
   if (n > 1) {
     __ LoadClass(R8, R0, R4);
     // Compute instance type arguments into R4.
     Label has_no_type_arguments;
     __ LoadObject(R4, Object::null_object());
     __ ldr(R9, FieldAddress(
                    R8, Class::type_arguments_field_offset_in_words_offset()));
     __ CompareImmediate(R9, Class::kNoTypeArguments);
     __ b(&has_no_type_arguments, EQ);
     __ add(R9, R0, Operand(R9, LSL, 2));
     __ ldr(R4, FieldAddress(R9, 0));
     __ Bind(&has_no_type_arguments);
   }
   __ LoadClassId(R8, R0);
   // R0: instance.
-  // R1: instantiator type arguments (only if n == 4, can be raw_null).
-  // R2: function type arguments (only if n == 4, can be raw_null).
+  // R2: instantiator type arguments (only if n == 4, can be raw_null).
+  // R1: function type arguments (only if n == 4, can be raw_null).
   // R3: SubtypeTestCache.
   // R8: instance class id.
   // R4: instance type arguments (null if none), used only if n > 1.
   __ ldr(R3, FieldAddress(R3, SubtypeTestCache::cache_offset()));
   __ AddImmediate(R3, Array::data_offset() - kHeapObjectTag);
 
   Label loop, found, not_found, next_iteration;
   // R3: entry start.
   // R8: instance class id.
   // R4: instance type arguments (still null if closure).
@@ skipping 14 matching lines @@
     __ b(&next_iteration, NE);
     __ ldr(R9,
            Address(R3, kWordSize * SubtypeTestCache::kInstanceTypeArguments));
     __ cmp(R9, Operand(R4));
     if (n == 2) {
       __ b(&found, EQ);
     } else {
       __ b(&next_iteration, NE);
       __ ldr(R9, Address(R3, kWordSize *
                                  SubtypeTestCache::kInstantiatorTypeArguments));
-      __ cmp(R9, Operand(R1));
+      __ cmp(R9, Operand(R2));
       __ b(&next_iteration, NE);
       __ ldr(R9,
              Address(R3, kWordSize * SubtypeTestCache::kFunctionTypeArguments));
-      __ cmp(R9, Operand(R2));
+      __ cmp(R9, Operand(R1));
       __ b(&found, EQ);
     }
   }
   __ Bind(&next_iteration);
   __ AddImmediate(R3, kWordSize * SubtypeTestCache::kTestEntryLength);
   __ b(&loop);
   // Fall through to not found.
   __ Bind(&not_found);
   __ LoadObject(R1, Object::null_object());
   __ Ret();
 
   __ Bind(&found);
   __ ldr(R1, Address(R3, kWordSize * SubtypeTestCache::kTestResult));
   __ Ret();
 }
 
 
 // Used to check class and type arguments. Arguments passed in registers:
 // LR: return address.
 // R0: instance (must be preserved).
+// R2: unused.
 // R1: unused.
-// R2: unused.
 // R3: SubtypeTestCache.
 // Result in R1: null -> not found, otherwise result (true or false).
 void StubCode::GenerateSubtype1TestCacheStub(Assembler* assembler) {
   GenerateSubtypeNTestCacheStub(assembler, 1);
 }
 
 
 // Used to check class and type arguments. Arguments passed in registers:
 // LR: return address.
 // R0: instance (must be preserved).
+// R2: unused.
 // R1: unused.
-// R2: unused.
 // R3: SubtypeTestCache.
 // Result in R1: null -> not found, otherwise result (true or false).
 void StubCode::GenerateSubtype2TestCacheStub(Assembler* assembler) {
   GenerateSubtypeNTestCacheStub(assembler, 2);
 }
 
 
 // Used to check class and type arguments. Arguments passed in registers:
 // LR: return address.
 // R0: instance (must be preserved).
-// R1: instantiator type arguments (can be raw_null).
-// R2: function type arguments (can be raw_null).
+// R2: instantiator type arguments (can be raw_null).
+// R1: function type arguments (can be raw_null).
 // R3: SubtypeTestCache.
 // Result in R1: null -> not found, otherwise result (true or false).
 void StubCode::GenerateSubtype4TestCacheStub(Assembler* assembler) {
   GenerateSubtypeNTestCacheStub(assembler, 4);
 }
 
 
 // Return the current stack pointer address, used to do stack alignment checks.
 void StubCode::GenerateGetStackPointerStub(Assembler* assembler) {
   __ mov(R0, Operand(SP));
@@ skipping 434 matching lines @@
 }
 
 
 void StubCode::GenerateAsynchronousGapMarkerStub(Assembler* assembler) {
   __ bkpt(0);
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM