ShiftUnsignedRight

(twinBASIC) Shifts the bits of an integral value right by a given number of positions, filling the vacated high-order bits with zeros.

Syntax: ShiftUnsignedRight( number, shiftamount )

number
required An expression of an integral type: Byte, Integer, Long, LongLong, LongPtr, Currency or Boolean. Any other type, a Variant included, is compile error TB5023, first argument must be a simple integral type.
shiftamount
required A numeric expression giving the number of bit positions to shift. It is converted to a Long.

The result has the type of number. ShiftUnsignedRight treats number as unsigned: the vacated high-order bits are always zero, so a negative value becomes a positive one. This is a logical shift. The >> operator makes an arithmetic shift instead, copying the sign bit into the vacated bits, so for a negative Integer, Long, LongLong or LongPtr the two differ: a Long holding &H80000001, shifted right by 1, is &HC0000000 with >> and &H40000000 with ShiftUnsignedRight. For a value that is not negative, and for a Byte, they give the same result.

A Currency is shifted as the 64-bit integer that stores it, which is its value multiplied by 10,000. A LongPtr has 32 or 64 bits, as the build is 32-bit or 64-bit.

A shift by as many bits as the type holds, or more, gives 0. A negative shiftamount raises no error, but gives no useful result.

With constant arguments, the call is evaluated when the code is compiled, so it can be used in a Const declaration, an Enum member’s value or a Case expression.

Note

ShiftUnsignedRight is a twinBASIC extension. VBA and VB6 have no function of this name: a call to it is the compile error Sub or Function not defined.

Example 

Dim Value As Long = &H80000001
Debug.Print Hex(ShiftUnsignedRight(Value, 1))   ' 40000000
Debug.Print Hex(Value >> 1)                     ' C0000000
Debug.Print ShiftUnsignedRight(Value, 32)       ' 0

See Also