Побитовые операции

/* 
 * bitAnd - x&y using only ~ and | 
 *   Example: bitAnd(6, 5) = 4
 *   Legal ops: ~ |
 *   Max ops: 8
 *   Hint: recall De Morgan's laws
 */
int bitAnd(int x, int y) {
    return ~(~x|~y);   // TODO: your implementation goes here
}

/* 
 * nthBit - return n-th bit in x
 *   Example: bitAnd(4, 1) = 0, bitAnd(4, 3) = 1
 *   Legal ops: >> &
 *   Max ops: 4
 */
int nthBit(int x, int n) {
    return (x>>n) &1;
    // TODO: your implementation goes here
}

/* 
 * setFirstNBits - returns a number with first (least significant) bits n set
 *   Example: setFirstNBits(3) = 7, setFirstNBits(0) = 0
 *   Legal ops: << -
 *   Max ops: 4
 *   Hint: 2^n - 1
 */
int setFirstNBits(int n) {
    // TODO: your implementation goes here
}

/* 
 * fromNtoMBits - returns a number composed from bits n to m
 *   Example: fromNtoMBits(4, 3, 5) = 1, fromNtoMBits(12, 3, 5) = 3
 *   Legal ops: >> & - setFirstNBits
 *   Max ops: 4
 */
int fromNtoMBits(int x, int n, int m) {
    // TODO: your implementation goes here
}

/* 
 * thirdBits - return word with every third bit (starting from the least 
                significant bit, LSB) set to 1 and the rest set to 0
 *   thirdBits() & 1 == 1, thirdBits() & 8 == 8, etc.
 *   Legal ops: ! ~ & ^ | + << >>
 *   Max ops: 8
 */
int thirdBits(void) {
    // TODO: your implementation goes here
}

int setFirstNBits( int n ) {
    int r = 0;
    while ( n-- ) {
        r = (r << 1) | 1;
    }
    return r;
}

int setFirstNBits( int n ) {
    return (1 << n) - 1;
}

/* 
 * fromNtoMBits - returns a number composed from bits n to m
 *   Example: fromNtoMBits(4, 3, 5) = 1, fromNtoMBits(12, 3, 5) = 3
 *   Legal ops: >> & - setFirstNBits
 *   Max ops: 4
 */
int fromNtoMBits( int x, int n, int m ) {
    return (x >> (n - 1)) & setFirstNBits( m - n );
}

/* 
 * thirdBits - return word with every third bit (starting from the least 
                significant bit, LSB) set to 1 and the rest set to 0
 *   thirdBits() & 1 == 1, thirdBits() & 8 == 8, etc.
 *   Legal ops: ! ~ & ^ | + << >>
 *   Max ops: 8
 */
int thirdBits() {
    return 0x49249249;
}

/* 
 * thirdBits - return word with every third bit (starting from the least 
                significant bit, LSB) set to 1 and the rest set to 0
 *   thirdBits() & 1 == 1, thirdBits() & 8 == 8, etc.
 *   Legal ops: ! ~ & ^ | + << >>
 *   Max ops: 8
 */
int thirdBits(void) {
    // TODO: your implementation goes here
}
 
 
/* 
 * bitXor - x^y using only ~ and & 
 *   Example: bitXor(4, 5) = 1
 *   Legal ops: ~ &
 *   Max ops: 10
 *   Hint: compare the result of (0 xor 1) with (~0 & 1), then (0 & ~1). 
            The idea is already emerged here. Just test it over other 
            combinations ((1 xor 0), (0 xor 0), etc.).
 */
int bitXor(int x, int y) {
    // TODO: your implementation goes here
}
 
/* 
 * fitsBits - return 1 if x can be represented as an 
 *  n-bit, two's complement integer.
 *   1 <= n <= 32
 *   Examples: fitsBits(5,3) = 0, fitsBits(-4,3) = 1
 *   Legal ops: ! ~ & ^ | + << >>
 *   Max ops: 15
 */
int fitsBits(int x, int n) {
    // TODO: your implementation goes here
}
 
/* 
 * sign - return 1 if positive, 0 if zero, and -1 if negative
 *  Examples: sign(130) = 1
 *            sign(-23) = -1
 *  Legal ops: ! ~ & ^ | + << >>
 *  Max ops: 10
 */
int sign(int x) {
    // TODO: your implementation goes here
}
/* 
 * getByte - Extract byte n from word x
 *   Bytes numbered from 0 (LSB) to 3 (MSB)
 *   Examples: getByte(0x12345678,1) = 0x56
 *   Legal ops: ! ~ & ^ | + << >>
 *   Max ops: 6
 */
int getByte(int x, int n) {
    // TODO: your implementation goes here
}

unsigned int bitXor(unsigned int x, unsigned int y)
{
    return ~(~(x&~y) & ~(~x&y));
}

int nthBit(int x, int n) {
    return ((x << 1) >> n) & 1;
}

return return (x>>/*BEGIN:constant*/((sizeof(int)<<3)-1)/*END*/)|!!x;

/* 
 * fitsBits - return 1 if x can be represented as an 
 *  n-bit, two's complement integer.
 *   1 <= n <= 32
 *   Examples: fitsBits(5,3) = 0, fitsBits(-4,3) = 1
 *   Legal ops: ! ~ & ^ | + << >>
 *   Max ops: 15
 */
int fitsBits(int x, int n) {
    // TODO: your implementation goes here
}