_SHR - QB64Official/qb64 GitHub Wiki

The _SHR function is used to shift the bits of a numerical value to the right.

Syntax

result = _SHR(numericalVariable, numericalValue)

Parameter(s)

  • numericalVariable is the variable to shift the bits of and can be of the following types: INTEGER, LONG, _INTEGER64, or _BYTE.
  • Integer values can be signed or _UNSIGNED.
  • numericalValue the number of places to shift the bits.
  • While 0 is a valid value it will have no affect on the variable being shifted.

Description

  • Allows for division of a value by 2 faster than normal division (see example 2 below).
  • Bits that reach the end of a variables bit count are dropped.
  • The type of variable used to store the results should match the type of the variable being shifted.
  • NOTE: When dealing with SIGNED variables, shifting the bits right will leave the sign bit set. This is due to how C++ deals with bit shifting under the hood.

Availability

  • Version 1.3 and up.

Example(s)


A~%% = 128 'set left most bit of an_UNSIGNED _BYTE
PRINT A~%%
PRINT _SHR(A~%%,7)
PRINT _SHR(A~%%,8) 'shift the bit off the right 'edge'



 128
 1
 0



A~%% = 128
FOR I%% = 0 TO 8
    PRINT _SHR(A~%%, I%%)
NEXT I%%



 128
  64
  32
  16
  8
  4
  2
  1
  0

See Also