Bit Fiddling

This code has been declared by its author to be Public Domain code.

Bit Fiddling by Shortwind

2010

Short commands to SetBit, ClearBit, ToggleBit, and ReadBit of a Integer. Easily adapted to Byte or Long.

'x=the Int with the value, bit is the bit to set, ie. 0-31

Function SetBit:Int(x:Int, bit:Int)
 	Return x | (1 Shl bit)
End Function

Function ClearBit:Int(x:Int, bit:Int)
	Return x & ~(1 Shl bit)
End Function

Function ToggleBit:Int(x:Int, bit:Int)
	Return x ~ (1 Shl bit)
End Function

Function ReadBit:Int(x:Int, bit:Int) 'This function returns 0 or 1...
	If (x & (1 Shl bit)) Return 1
	Return 0 
End Function

Comments

Shortwind

2010

Why are these simple commands not part of the standard language? They could easily be overloaded in that respect if they were.

TaskMaster

2010

Maybe because they are so simple?

Shortwind

2010

Ha ha. Good one Taskmaster. Even though I see this come up all the time, in all languages, not just here. Seriously, I was wondering why this isn't part of a standard language, there are endless uses for functions of this type, and to be able to overload them would be very useful. (Or does the standard C library, for example, have these functions???)

Charrua

2010

hi, bit manipulation are a must in a microcontroller isa (instruction set architecture) but, normally not implemented in microprocesors:they are word based not bit based. Bit manipulation aren't needed in the day by day, using high level languajes. But soner or later this kind of function are needed. Flags are everywhere and Boolean variables only need a bit, not the double word any high level lenguaje use.

Juan

SebHoll

2010

This can be optimized like so:

Function ReadBit:Int(x:Int, bit:Int) 'This function returns 0 or 1...
	Return (x Shr bit) & 1
End Function

Code Archives Forum