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74 lines
1.6 KiB
Markdown
74 lines
1.6 KiB
Markdown
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The [_SHL](_SHL) function is used to shift the bits of a numerical value to the left.
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## Syntax
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> result = [_SHL](_SHL)(numericalVariable, numericalValue)
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## Parameter(s)
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* numericalVariable is the variable to shift the bits of and can be of the following types: [INTEGER](INTEGER), [LONG](LONG),[_INTEGER64](_INTEGER64), or [_BYTE](_BYTE).
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* Integer values can be signed or [_UNSIGNED](_UNSIGNED).
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* numericalValue is the number of places to shift the bits.
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* While 0 is a valid value it will have no affect on the variable being shifted.
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## Description
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* Allows for multiplication of a value by 2 faster than normal multiplication (see example 2 below).
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* 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).
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* The type of variable used to store the results should match the type of the variable being shifted.
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## Availability
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* Version 1.3 and up.
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## Example(s)
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```vb
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A~%% = 1 'set right most bit of an_UNSIGNED _BYTE
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PRINT A~%%
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PRINT _SHL(A~%%,7)
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B~%% = _SHL(A~%%,8) 'shift the bit off the left 'edge'
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PRINT B~%%
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```
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```text
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1
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128
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0
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```
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```vb
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A~%% = 1
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FOR I%% = 0 TO 8
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PRINT _SHL(A~%%, I%%)
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NEXT I%%
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```
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```text
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1
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2
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4
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8
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16
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32
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64
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128
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256
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```
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* Note: When directly [PRINT](PRINT)ing to screen, the result is calculated internally using a larger variable type so the left most bit is carried to the next value.
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* To avoid this store the result in a variable of the same type before printing.
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## See Also
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* [_SHR](_SHR), [INTEGER](INTEGER), [LONG](LONG)
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* [_BYTE](_BYTE), [_INTEGER64](_INTEGER64)
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