SHR: Difference between revisions

Revision as of 00:07, 22 April 2022

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

result = _SHR(numericalVariable, numericalValue)

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.

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.

Example 1:

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

Example 2:

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

@@ Line 43: / Line 43: @@
 {{Cl|FOR}} I%% = 0 {{Cl|TO}} 8
      {{Cl|PRINT}} {{Cl|_SHR}}(A~%%, I%%)
-{{Cl|NEXT I%%}}
+{{Cl|FOR...NEXT|NEXT}} I%%
 {{CodeEnd}}
 {{OutputStart}}