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Bitwise operators treat their operands as a set of 32 bits (zeros and ones), rather than as decimal, hexadecimal, or octal numbers. For example, the decimal number nine has a binary representation of 1001. Bitwise operators perform their operations on such binary representations, but they return standard MetaScript numerical values.
The following table summarizes MetaScript's bitwise operators:
| Operator | Usage | Description |
|---|---|---|
| Bitwise AND | a & b | Returns a one in each bit position for which the corresponding bits of both operands are ones. |
| Bitwise OR | a | b | Returns a one in each bit position for which the corresponding bits of either or both operands are ones. |
| Bitwise XOR | a ^ b | Returns a one in each bit position for which the corresponding bits of either but not both operands are ones. |
| Bitwise NOT | ~ a | Inverts the bits of its operand. |
| Left shift | a << b | Shifts a in binary representation b bits to left, shifting in zeros from the right. |
| Sign-propagating right shift | a >> b | Shifts a in binary representation b bits to right, discarding bits shifted off. |
| Zero-fill right shift | a >>> b | Shifts a in binary representation b bits to the right, discarding bits shifted off, and shifting in zeros from the left. |
Bitwise Logical Operators
Conceptually, the bitwise logical operators work as follows:
The operands are converted to thirty-two-bit integers and expressed by a series of bits (zeros and ones).
Each bit in the first operand is paired with the corresponding bit in the second operand: first bit to first bit, second bit to second bit, and so on.
The operator is applied to each pair of bits, and the result is constructed bitwise.
For example, the binary representation of nine is 1001, and the binary representation of fifteen is 1111. So, when the bitwise operators are applied to these values, the results are as follows:
15 & 9 yields 9 (1111 & 1001 = 1001)
15 | 9 yields 15 (1111 | 1001 = 1111)
15 ^ 9 yields 6 (1111 ^ 1001 = 0110)
Bitwise Shift Operators
The bitwise shift operators take two operands: the first is a quantity to be shifted, and the second specifies the number of bit positions by which the first operand is to be shifted. The direction of the shift operation is controlled by the operator used.
Shift operators convert their operands to thirty-two-bit integers and return a result of the same type as the left operator.
<< (Left Shift)
This operator shifts the first operand the specified number of bits to the left. Excess bits shifted off to the left are discarded. Zero bits are shifted in from the right.
For example, 9<<2 yields thirty-six, because 1001 shifted two bits to the left becomes 100100, which is thirty-six.
>> (Sign-Propagating Right Shift)
This operator shifts the first operand the specified number of bits to the right. Excess bits shifted off to the right are discarded. Copies of the leftmost bit are shifted in from the left.
For example, 9>>2 yields two, because 1001 shifted two bits to the right becomes 10, which is two. Likewise, -9>>2 yields -3, because the sign is preserved.
>>> (Zero-Fill Right Shift)
This operator shifts the first operand the specified number of bits to the right. Excess bits shifted off to the right are discarded. Zero bits are shifted in from the left.
For example, 19>>>2 yields four, because 10011 shifted two bits to the right becomes 100, which is four. For non-negative numbers, zero-fill right shift and sign-propagating right shift yield the same result.