[Intepreter] Extend and move Register class.

test/unittests/interpreter/bytecodes-unittest.cc

+// Copyright 2014 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 <vector>
+
+#include "src/v8.h"
+
+#include "src/interpreter/bytecodes.h"
+#include "test/unittests/test-utils.h"
+
+
+namespace v8 {
+namespace internal {
+namespace interpreter {
+
+TEST(OperandConversion, Registers) {
+  for (int i = 0; i < 128; i++) {
+    uint8_t operand_value = Register(i).ToOperand();
+    Register r = Register::FromOperand(operand_value);
+    CHECK_EQ(i, r.index());
+  }
+}
+
+
+TEST(OperandConversion, Parameters) {
+  std::vector<int> parameter_counts{7, 13, 99};

[rmcilroy, 2015/09/02 15:22:29]

Unfortunately I don't think this will work on Mac since it is relying on c++11
library features. :(

Could you just do something like:
int parameter_counts[] = {7, 13, 99};
size_t count = sizeof parameter_counts / sizeof(int);
for (size_t p = 0; p < count; p++) {...

[oth, 2015/09/02 16:28:06]

Done, but with sizeof(parameter_counts[0]) to preserve type.

+
+  for (size_t p = 0; p < parameter_counts.size(); p++) {
+    int parameter_count = parameter_counts[p];
+    for (int i = 0; i <= parameter_count; i++) {
+      Register r = Register::FromParameterIndex(i, parameter_count);
+      uint8_t operand_value = r.ToOperand();
+      Register s = Register::FromOperand(operand_value);
+      CHECK_EQ(i, s.ToParameterIndex(parameter_count));
+    }
+  }
+}
+
+
+TEST(OperandConversion, RegistersParametersNoOverlap) {
+  uint8_t operand_count[255] = {0};
+
+  for (int i = 0; i <= Register::kMaxRegisterIndex; i++) {
+    Register r = Register(i);
+    uint8_t operand = r.ToOperand();
+    operand_count[operand] += 1;
+    CHECK_EQ(operand_count[operand], 1);
+  }
+
+  int parameter_count = Register::MaxParameterIndex();
+  for (int i = 0; i <= parameter_count; i++) {
+    Register r = Register::FromParameterIndex(i, parameter_count);
+    uint8_t operand = r.ToOperand();
+    operand_count[operand] += 1;
+    CHECK_EQ(operand_count[operand], 1);
+  }
+}
+
+}  // namespace interpreter
+}  // namespace internal
+}  // namespace v8