SHL

The _SHL function is used to shift the bits of a numerical value to the left.

Syntax

result = _SHL(numericalVariable, numericalValue)

Parameters

• 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 is 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 multiplication of a value by 2 faster than normal multiplication (see example 2 below).
• Bits that reach the end of a variable's bit count are dropped (when using a variable of the same type - otherwise they will carry over).
• The type of variable used to store the results should match the type of the variable being shifted.

Availability

• Version 1.3 and up.

Examples

Example 1:

A~%% = 1 'set right most bit of an_UNSIGNED _BYTE PRINT A~%% PRINT _SHL(A~%%,7) B~%% = _SHL(A~%%,8) 'shift the bit off the left 'edge' PRINT B~%%

1 128 0

Example 2:

A~%% = 1 FOR I%% = 0 TO 8 PRINT _SHL(A~%%, I%%) NEXT I%%

1 2 4 8 16 32 64 128 256

• Note: When directly PRINTing to screen, the result is calculated internally using a larger variable type so the left most bit is carried to the next value.
  • To avoid this store the result in a variable of the same type before printing.

See also

• _SHR, _ROL, _ROR
• _BYTE, INTEGER
• LONG, _INTEGER64

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