[Interpreter] Adds shift operators to interpreter

src/interpreter/interpreter.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/interpreter/interpreter.h"
 
 #include "src/code-factory.h"
 #include "src/compiler.h"
 #include "src/compiler/interpreter-assembler.h"
 #include "src/factory.h"
@@ skipping 357 matching lines @@
 
 
 // Mod <src>
 //
 // Modulo register <src> by accumulator.
 void Interpreter::DoMod(compiler::InterpreterAssembler* assembler) {
   DoBinaryOp(Runtime::kModulus, assembler);
 }
 
 
+// ShiftLeft <src>
+//
+// Left shifts accumulator by the count specified in register <src>.

[rmcilroy, 2015/10/08 14:53:07]

"accumulator" -> "the accumulator"

[oth, 2015/10/08 16:11:38]

Shouldn't it be Left shifts the register <src> by the value specified in the
accumulator? Same with the doc comments for ShiftRight and ShiftRightLogical.

+// accumulator is converted to a int32 and register <src> to uint32

[rmcilroy, 2015/10/08 14:53:07]

nit "accumulator" -> "The accumulator" (it's the start of a sentence)

[rmcilroy, 2015/10/08 14:53:07]

nit - a int32 -> an int32

+// before the operation. 5 lsb bits from register <src> are used as count.

[rmcilroy, 2015/10/08 14:53:07]

nit - move "." from after "count" to after "0x1F)"

+// i.e. accumulator << (<src> & 0x1F)
+void Interpreter::DoShiftLeft(compiler::InterpreterAssembler* assembler) {
+  DoBinaryOp(Runtime::kShiftLeft, assembler);
+}
+
+
+// ShiftRight <src>
+//
+// Right shifts accumulator by the count specified in register <src>.
+// Result is sign extended.

[rmcilroy, 2015/10/08 14:53:07]

Same comments here. Also, either bring the next sentence onto this line, or add
a blank comment line if you want to make a paragraph.

+// accumulator is converted to a int32 and register <src> to uint32
+// before the operation. 5 lsb bits from register <src> are used as count.
+// i.e. accumulator >> (<src> & 0x1F)
+void Interpreter::DoShiftRight(compiler::InterpreterAssembler* assembler) {
+  DoBinaryOp(Runtime::kShiftRight, assembler);
+}
+
+
+// ShiftRightLogical <src>
+//
+// Right Shifts accumulator by the count specified in register <src>.
+// Result is zero-filled.

[rmcilroy, 2015/10/08 14:53:07]

ditto

+// accumulator and register <src> are converted to uint32 before the operation
+// lsb bits from register <src> are used as count.
+// i.e. accumulator >> (<src> & 0x1F)
+void Interpreter::DoShiftRightLogical(
+    compiler::InterpreterAssembler* assembler) {
+  DoBinaryOp(Runtime::kShiftRightLogical, assembler);
+}
+
+
 // LogicalNot
 //
 // Perform logical-not on the accumulator, first casting the
 // accumulator to a boolean value if required.
 void Interpreter::DoLogicalNot(compiler::InterpreterAssembler* assembler) {
   Node* accumulator = __ GetAccumulator();
   Node* result = __ CallRuntime(Runtime::kInterpreterLogicalNot, accumulator);
   __ SetAccumulator(result);
   __ Dispatch();
 }
@@ skipping 220 matching lines @@
 //
 // Return the value in the accumulator.
 void Interpreter::DoReturn(compiler::InterpreterAssembler* assembler) {
   __ Return();
 }
 
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8