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68 lines
1.8 KiB
Plaintext
68 lines
1.8 KiB
Plaintext
{{DISPLAYTITLE:_SHL}}
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The [[_SHL]] function is used to shift the bits of a numerical value to the left.
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{{PageSyntax}}
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:{{Parameter|result}} = [[_SHL]]({{Parameter|numericalVariable}}, {{Parameter|numericalValue}})
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{{PageParameters}}
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* {{Parameter|numericalVariable}} is the variable to shift the bits of and can be of the following types: [[INTEGER]], [[LONG]],[[_INTEGER64]], or [[_BYTE]].
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* Integer values can be signed or [[_UNSIGNED]].
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* {{Parameter|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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{{PageDescription}}
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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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{{PageAvailability}}
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* Version 1.3 and up.
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{{PageExamples}}
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''Example 1:''
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{{CodeStart}}A~%% = 1 'set right most bit of an{{Cl|_UNSIGNED}} {{Cl|_BYTE}}
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{{Cl|PRINT}} A~%%
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{{Cl|PRINT}} {{Cl|_SHL}}(A~%%,7)
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B~%% = {{Cl|_SHL}}(A~%%,8) 'shift the bit off the left 'edge'
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{{Cl|PRINT}} B~%%
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{{CodeEnd}}
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{{OutputStart}}
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1
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128
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0
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{{OutputEnd}}
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''Example 2:''
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{{CodeStart}}
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A~%% = 1
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{{Cl|FOR}} I%% = 0 {{Cl|TO}} 8
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{{Cl|PRINT}} {{Cl|_SHL}}(A~%%, I%%)
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{{Cl|NEXT}} I%%
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{{CodeEnd}}
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{{OutputStart}}
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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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{{OutputEnd}}
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* Note: When directly [[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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{{PageSeeAlso}}
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* [[_SHR]], [[INTEGER]], [[LONG]]
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* [[_BYTE]], [[_INTEGER64]]
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{{PageNavigation}}
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