Provide BitField64 utility class.

test/cctest/test-conversions.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 231 matching lines @@
 TEST(ExponentNumberStr) {
   UnicodeCache uc;
   CHECK_EQ(1e1, StringToDouble(&uc, "1e1", NO_FLAGS));
   CHECK_EQ(1e1, StringToDouble(&uc, "1e+1", NO_FLAGS));
   CHECK_EQ(1e-1, StringToDouble(&uc, "1e-1", NO_FLAGS));
   CHECK_EQ(1e100, StringToDouble(&uc, "1e+100", NO_FLAGS));
   CHECK_EQ(1e-100, StringToDouble(&uc, "1e-100", NO_FLAGS));
   CHECK_EQ(1e-106, StringToDouble(&uc, ".000001e-100", NO_FLAGS));
 }
 
-class OneBit1: public BitField<uint32_t, 0, 1> {};
-class OneBit2: public BitField<uint32_t, 7, 1> {};
-class EightBit1: public BitField<uint32_t, 0, 8> {};
-class EightBit2: public BitField<uint32_t, 13, 8> {};
 
 TEST(BitField) {
   uint32_t x;
 
   // One bit bit field can hold values 0 and 1.
+  class OneBit1: public BitField<uint32_t, 0, 1> {};
+  class OneBit2: public BitField<uint32_t, 7, 1> {};
   CHECK(!OneBit1::is_valid(static_cast<uint32_t>(-1)));
   CHECK(!OneBit2::is_valid(static_cast<uint32_t>(-1)));
   for (int i = 0; i < 2; i++) {
     CHECK(OneBit1::is_valid(i));
     x = OneBit1::encode(i);
     CHECK_EQ(i, OneBit1::decode(x));
 
     CHECK(OneBit2::is_valid(i));
     x = OneBit2::encode(i);
     CHECK_EQ(i, OneBit2::decode(x));
   }
   CHECK(!OneBit1::is_valid(2));
   CHECK(!OneBit2::is_valid(2));
 
   // Eight bit bit field can hold values from 0 tp 255.
+  class EightBit1: public BitField<uint32_t, 0, 8> {};
+  class EightBit2: public BitField<uint32_t, 13, 8> {};
   CHECK(!EightBit1::is_valid(static_cast<uint32_t>(-1)));
   CHECK(!EightBit2::is_valid(static_cast<uint32_t>(-1)));
   for (int i = 0; i < 256; i++) {
     CHECK(EightBit1::is_valid(i));
     x = EightBit1::encode(i);
     CHECK_EQ(i, EightBit1::decode(x));
     CHECK(EightBit2::is_valid(i));
     x = EightBit2::encode(i);
     CHECK_EQ(i, EightBit2::decode(x));
   }
   CHECK(!EightBit1::is_valid(256));
   CHECK(!EightBit2::is_valid(256));
 }
+
+
+TEST(BitField64) {
+  uint64_t x;
+
+  // Test most significant bits.
+  class UpperBits: public BitField64<int, 61, 3> {};
+  x = V8_2PART_UINT64_C(0xE0000000, 00000000);
+  CHECK(x == UpperBits::encode(7));
+  CHECK_EQ(7, UpperBits::decode(x));
+
+  // Test the 32/64-bit boundary bits.
+  class MiddleBits: public BitField64<int, 31, 2> {};
+  x = V8_2PART_UINT64_C(0x00000001, 80000000);
+  CHECK(x == MiddleBits::encode(3));
+  CHECK_EQ(3, MiddleBits::decode(x));
+}