public static int RotateLeft(int value, int bitCount, out bool carry)
{
var bitMaskUpToEnd = BitMath.CreateBitmaskUpTo(bitCount);
var remaining = value << 1;
var carried = value >> (bitCount - 1);
carry = (carried & 1) == 1;
return((remaining | carried) & bitMaskUpToEnd);
}
/// <summary>
/// Shifts all bits right.
/// </summary>
public static int LogicalShiftRight(
int value,
int bitCount,
out bool carry)
{
carry = (value & 1) == 1;
var bitMaskUpToEnd = BitMath.CreateBitmaskUpTo(bitCount);
return((value & bitMaskUpToEnd) >> 1);
}
/// <summary>
/// Shifts the bits right without modifying the sign bit (which is MSB).
/// </summary>
/*public static int ArithmeticShiftRight(
* int value,
* int bitCount,
* out bool carry) {
*
* }*/
/// <summary>
/// Shifts all bits left.
/// </summary>
public static int LogicalShiftLeft(
int value,
int bitCount,
out bool carry)
{
carry = ((value >> (bitCount - 1)) & 1) == 1;
var bitMaskUpToEnd = BitMath.CreateBitmaskUpTo(bitCount);
return((value << 1) & bitMaskUpToEnd);
}
public static int RotateLeftThroughCarry(
int value,
int bitCount,
ref bool carry)
{
var bitMaskUpToEnd = BitMath.CreateBitmaskUpTo(bitCount);
var remaining = value << 1;
var overflow = value >> (bitCount - 1);
var carried = carry ? 1 : 0;
carry = (overflow & 1) == 1;
return((remaining | carried) & bitMaskUpToEnd);
}
public static int RotateRightThroughCarry(
int value,
int bitCount,
ref bool carry)
{
var bitMaskUpToEnd = BitMath.CreateBitmaskUpTo(bitCount);
var bitMaskAtMsb = BitMath.CreateBitmaskAt(bitCount - 1);
value &= bitMaskUpToEnd;
var remaining = value >> 1;
var carried = carry ? bitMaskAtMsb : 0;
carry = (value & 1) == 1;
return((remaining | carried) & bitMaskUpToEnd);
}
public static int CreateBitmaskUpTo(int bitCount) => BitMath.CreateBitmaskAt(bitCount) - 1;