diff --git a/include/utils/BitSet.h b/include/utils/BitSet.h
index 19c03d1..1ca75fe 100644
--- a/include/utils/BitSet.h
+++ b/include/utils/BitSet.h
@@ -40,7 +40,7 @@
     inline void clear() { value = 0; }
 
     // Returns the number of marked bits in the set.
-    inline uint32_t count() const { return __builtin_popcount(value); }
+    inline uint32_t count() const { return __builtin_popcountl(value); }
 
     // Returns true if the bit set does not contain any marked bits.
     inline bool isEmpty() const { return ! value; }
@@ -59,15 +59,15 @@
 
     // Finds the first marked bit in the set.
     // Result is undefined if all bits are unmarked.
-    inline uint32_t firstMarkedBit() const { return __builtin_clz(value); }
+    inline uint32_t firstMarkedBit() const { return __builtin_clzl(value); }
 
     // Finds the first unmarked bit in the set.
     // Result is undefined if all bits are marked.
-    inline uint32_t firstUnmarkedBit() const { return __builtin_clz(~ value); }
+    inline uint32_t firstUnmarkedBit() const { return __builtin_clzl(~ value); }
 
     // Finds the last marked bit in the set.
     // Result is undefined if all bits are unmarked.
-    inline uint32_t lastMarkedBit() const { return 31 - __builtin_ctz(value); }
+    inline uint32_t lastMarkedBit() const { return 31 - __builtin_ctzl(value); }
 
     // Finds the first marked bit in the set and clears it.  Returns the bit index.
     // Result is undefined if all bits are unmarked.
@@ -96,7 +96,7 @@
     // Gets the index of the specified bit in the set, which is the number of
     // marked bits that appear before the specified bit.
     inline uint32_t getIndexOfBit(uint32_t n) const {
-        return __builtin_popcount(value & ~(0xffffffffUL >> n));
+        return __builtin_popcountl(value & ~(0xffffffffUL >> n));
     }
 
     inline bool operator== (const BitSet32& other) const { return value == other.value; }
@@ -119,6 +119,99 @@
 
 ANDROID_BASIC_TYPES_TRAITS(BitSet32)
 
+// A simple set of 64 bits that can be individually marked or cleared.
+struct BitSet64 {
+    uint64_t value;
+
+    inline BitSet64() : value(0ULL) { }
+    explicit inline BitSet64(uint64_t value) : value(value) { }
+
+    // Gets the value associated with a particular bit index.
+    static inline uint64_t valueForBit(uint32_t n) { return 0x8000000000000000ULL >> n; }
+
+    // Clears the bit set.
+    inline void clear() { value = 0ULL; }
+
+    // Returns the number of marked bits in the set.
+    inline uint32_t count() const { return __builtin_popcountll(value); }
+
+    // Returns true if the bit set does not contain any marked bits.
+    inline bool isEmpty() const { return ! value; }
+
+    // Returns true if the bit set does not contain any unmarked bits.
+    inline bool isFull() const { return value == 0xffffffffffffffffULL; }
+
+    // Returns true if the specified bit is marked.
+    inline bool hasBit(uint32_t n) const { return value & valueForBit(n); }
+
+    // Marks the specified bit.
+    inline void markBit(uint32_t n) { value |= valueForBit(n); }
+
+    // Clears the specified bit.
+    inline void clearBit(uint32_t n) { value &= ~ valueForBit(n); }
+
+    // Finds the first marked bit in the set.
+    // Result is undefined if all bits are unmarked.
+    inline uint32_t firstMarkedBit() const { return __builtin_clzll(value); }
+
+    // Finds the first unmarked bit in the set.
+    // Result is undefined if all bits are marked.
+    inline uint32_t firstUnmarkedBit() const { return __builtin_clzll(~ value); }
+
+    // Finds the last marked bit in the set.
+    // Result is undefined if all bits are unmarked.
+    inline uint32_t lastMarkedBit() const { return 63 - __builtin_ctzll(value); }
+
+    // Finds the first marked bit in the set and clears it.  Returns the bit index.
+    // Result is undefined if all bits are unmarked.
+    inline uint32_t clearFirstMarkedBit() {
+        uint64_t n = firstMarkedBit();
+        clearBit(n);
+        return n;
+    }
+
+    // Finds the first unmarked bit in the set and marks it.  Returns the bit index.
+    // Result is undefined if all bits are marked.
+    inline uint32_t markFirstUnmarkedBit() {
+        uint64_t n = firstUnmarkedBit();
+        markBit(n);
+        return n;
+    }
+
+    // Finds the last marked bit in the set and clears it.  Returns the bit index.
+    // Result is undefined if all bits are unmarked.
+    inline uint32_t clearLastMarkedBit() {
+        uint64_t n = lastMarkedBit();
+        clearBit(n);
+        return n;
+    }
+
+    // Gets the index of the specified bit in the set, which is the number of
+    // marked bits that appear before the specified bit.
+    inline uint32_t getIndexOfBit(uint32_t n) const {
+        return __builtin_popcountll(value & ~(0xffffffffffffffffULL >> n));
+    }
+
+    inline bool operator== (const BitSet64& other) const { return value == other.value; }
+    inline bool operator!= (const BitSet64& other) const { return value != other.value; }
+    inline BitSet64 operator& (const BitSet64& other) const {
+        return BitSet64(value & other.value);
+    }
+    inline BitSet64& operator&= (const BitSet64& other) {
+        value &= other.value;
+        return *this;
+    }
+    inline BitSet64 operator| (const BitSet64& other) const {
+        return BitSet64(value | other.value);
+    }
+    inline BitSet64& operator|= (const BitSet64& other) {
+        value |= other.value;
+        return *this;
+    }
+};
+
+ANDROID_BASIC_TYPES_TRAITS(BitSet32)
+
 } // namespace android
 
 #endif // UTILS_BITSET_H