AviSynth Syntax - Bit functions¶
The functions are bitwise operators. They manipulate individual bits within integer variables. This means that their arguments (being integers) are converted to binary numbers, the operation is performed on their bits, and the resulting binary number is converted back again.
BitAnd¶
BitAnd(int, int)
Returns the bitwise AND (sets bit to 1 if both bits are 1 and sets bit to 0 otherwise).
Examples:
BitAnd(5, 6) = 4 # since 5 = 101, 6 = 110, and 101&110 = 100
BitNot¶
BitNot(int)
Returns the bit-inversion (sets bit to 1 if bit is 0 and vice-versa).
Examples:
BitNOT(5) = -6
# since 5 = 101,
# and ~101 = 1111 1111 1111 1111 1111 1111 1111 1010 = -6
Note:
1111 1111 1111 1111 1111 1111 11111010 =
(2^32-1)-2^0-2^2 = 2^32-(1+2^0+2^2) =
(signed) -(1+2^0+2^2) =
-6.
BitOr¶
BitOr(int, int)
Returns the bitwise inclusive OR (sets bit to 1 if one of the bits (or both) is 1 and sets bit to 0 otherwise).
Examples:
BitOr(5, 6) = 7 # since 5 = 101, 6 = 110, and 101|110 = 111
BitOr(4, 2) = 6 # since 4 = 100, 2 = 010, and 100|010 = 110
BitXor¶
BitXor(int, int)
Returns the bitwise exclusive OR (sets bit to 1 if exactly one of the bits is 1 and sets bit to 0 otherwise).
Examples:
BitXor(5, 6) = 3 # since 5 = 101, 6 = 110, and 101^110 = 011
BitXor(4, 2) = 6 # since 4 = 100, 2 = 010, and 100^010 = 110
Bit Shift Left (BitLShift, BitShl, BitSal)¶
BitLShift(int, int)
BitShl(int, int)
BitSal(int, int)
Shift the bits of a number to the left.
Synonyms. Even more synonyms are: BitLShiftL, BitLShiftA, BitLShiftU, BitLShiftS
Examples:
Shifts the bits of the number 5 two bits to the left:
BitLShift(5, 2) = 20 (since 101 << 2 = 10100)
Bit shift right, signed (BitRShiftA, BitRShiftS, BitSar)¶
BitRShiftA(int, int)
BitRShiftS(int, int)
BitSar(int, int)
Shift the bits of an integer to the right. (Arithmetic, Sign bit fill, Right Shift)
Synonyms.
Examples:
Shifts the bits of the number -42 one bit to the right, treating it as signed:
BitRShiftA(-42, 1) = -21
# (since 1111 1111 1111 1111 1111 1111 1101 0110 >> 1
# = 1111 1111 1111 1111 1111 1111 1110 1011)
Bit shift right, unsigned (BitRShiftL, BitRShiftU, BitShr)¶
BitRShiftL(int, int)
BitRShiftU(int, int)
BitShr(int, int)
Shift the bits of an unsigned integer to the right. (Logical, zero fill, Right Shift)
Synonyms.
Examples:
Shifts the bits of the number -42 one bit to the right, treating it as unsigned:
BitRShiftL(-42, 1) = 2147483627
# (since 1111 1111 1111 1111 1111 1111 1101 0110 >> 1
# = 0111 1111 1111 1111 1111 1111 1110 1011)
Note:
-42 = -(1+2^0+2^3+2^5) = (unsigned) (2^32-1)-(2^0+2^3+2^5) =
1111 1111 1111 1111 1111 1111 1101 0110
Bit rotate left¶
BitLRotate(int, int)
BitRol(int, int)
Rotates the bits of an integer to the left by the number of bits specified in the second operand. For each rotation specified, the high order bit that exits from the left of the operand returns at the right to become the new low order bit.
Examples:
Rotates the bits of the number -2147483642 one bit to the left:
BitLRotate(-2147483642, 1) = 13
# (since 10000000000000000000000000000110 ROL 1
# = 00000000000000000000000000001101)
Bit rotate right¶
BitRRotateL(int, int)
BitRor(int, int)
Rotates the bits of an integer to the right by the number of bits specified in the second operand. For each rotation specified, the low order bit that exits from the right of the operand returns at the left to become the new high order bit.
Examples:
Rotates the bits of the number 13 one bit to the right:
BitRRotate(13, 1) = -2147483642
# (since 00000000000000000000000000001101 ROR 1
# = 10000000000000000000000000000110)
Bit test¶
BitTest(int, int)
BitTst(int, int)
Tests a single bit (that is, it returns true if its state is one, else it returns false). The second operand denotes the location of the bit which is specified as an offset from the low order end of the operand (starting at zero).
Examples:
Check the state of the fourth bit:
BitTest(3, 4) = False
BitTest(19, 4) = True
Check the state of the sign bit:
BitTest(-1, 31) = True
BitTest(2147483647, 31) = False
BitSet¶
BitSet(int, int)
Sets a single bit to one (so it sets its state to one). The second operand denotes the location of the bit which is specified as an offset from the low order end of the operand (starting at zero).
Examples:
Set the state of the fourth bit to one:
BitSet(3, 4) = 19
BitSet(19, 4) = 19
Set the state of the sign bit to one:
BitSet(-1, 31) = -1
BitSet(2147483647, 31) = -1
BitSetCount¶
BitSetCount(int [, int...])
Returns the total number of set bits in all supplied integer arguments.
Bit clear¶
BitClear(int, int)
BitClr(int, int)
Sets a single bit to zero (so it sets its state to zero). The second operand denotes the location of the bit which is specified as an offset from the low order end of the operand (starting at zero).
Examples:
Clear the bits of the number 5
BitClear(5, 0) = 4 (first bit is set to zero)
BitClear(5, 1) = 5 (second bit is already zero)
BitClear(5, 2) = 1 (third bit is set to zero)
BitClear(5, 3) = 5 (fourth bit is already zero)
Clear the state of the sign bit:
BitClear(-1, 31) = 2147483647
Bit change¶
BitChange(int, int)
BitChg(int, int)
Sets a single bit to its complement (so it changes the state of a single bit; 1 becomes 0 and vice versa). The second operand denotes the location of the bit which is specified as an offset from the low order end of the operand (starting at zero). The sign bit is bit 31.
Examples:
Change the state of the a bit of the number 5:
BitChange(5, 0) = 4 (first bit is set to zero)
BitChange(5, 1) = 7 (second bit is set to one)
BitChange(5, 2) = 1 (third bit is set to zero)
BitChange(5, 3) = 13 (fourth bit is set to one)
Change the state of the sign bit:
BitChange(-1, 31) = 2147483647
Changelog¶
Version |
Changes |
|---|---|
Avisynth 3.7.3 |
Fix bitrol/bitror when first argument is negative (Avisynth+ regression) |
Avisynth+ r2632 |
BitSetCount |
Avisynth 2.6 |
BitAnd, BitNot, BitOr, BitXor,
BitLShift, BitShl, BitSal,
BitRShiftA, BitRShiftS, BitSar,
BitRShiftL, BitRShiftU, BitShr,
BitRol, BitRor,
BitTest, BitTst,
BitSet, BitClear, BitClr,
BitChange, BitChg
|
Back to Internal functions.
$Date: 2024/01/15 13:38:34 $
