' LIBRARY - Logic Functions
' C.A.Roper - 2015/06/01
' Version 1.0
' _____________________________________________________________________________

' Bitwise Logic Functions
' _____________________________________________________________________________

' OnesComp%( Value% )
' Returns the BitWise NOT Function of Value% Equivalent to '~' operator in C

' BitGet( Value%, BitNumber )
' Returns the State ( 1 or 0 ) of BitNumber of Value%

' BitSet( Value%, BitNumber )
' Forces BitNumber of Value% to 1
' Returns the new Value%

' BitClr( Value%, BitNumber )
' Forces BitNumber of Value% to 0
' Returns the new Value%

' BitTgl( Value%, BitNumber )
' Toggles the State of BitNumber of Value%
' Returns the new Value%

' BitSet( Value%, BitNumber, BitState )
' Forces BitNumber of Value% to the State of BitState
' Where State is the Boolean Value of BitState,
' 0 or null = FALSE
' any other value = TRUE
' Returns the new Value%
' _____________________________________________________________________________

' Bitwise Stack Functions
' _____________________________________________________________________________

' A "Stack Overflow Error"
' Generated if > 64 Stack Entry's Result
' A "Stack Underflow Error"
' Generated if More Values are pulled than Entries Made

' BitPush( BitState )
' Pushes State into the Bottom of the Stack
' Where State is the Boolean Value of BitState,
' 0 or null = FALSE
' any other value = TRUE
' Increments Stack Pointer
' Updates the Stack
' Returns the New Stack

' BitPull()
' Pulls The State from the Bottom of the Stack
' Decrements the Stack Pointer
' Updates the Stack
' Returns the State Pulled

' BitSwap()
' Reverses the Order of the last two Entries in the Stack
' Stack Pointer is not effected
' Updates the Stack
' Returns the New Stack

' BitDup()
' Duplicates the Bottom Stack Entry
' Increments the Stack Pointer
' Updates the Stack
' Returns the new stack
' _____________________________________________________________________________

' Bitwise Logic Functions

FUNCTION OnesComp%(in%):OnesComp% = in% XOR &HFFFFFFFF:END FUNCTION
FUNCTION BitGet(in%, Bit):BitGet = (in% >> Bit) AND 1:END FUNCTION
FUNCTION BitSet(in%, Bit):BitSet = in% OR (1 << Bit):END FUNCTION
FUNCTION BitClr(in%, Bit):BitClr = in% AND OnesComp%(1 << Bit):END FUNCTION
FUNCTION BitPut(in%, Bit, Val):BitPut = BitClr(in%, Bit) OR ((NOT NOT Val) << Bit):END FUNCTION
FUNCTION BitTgl(in%, Bit):BitTgl = in% XOR (1 << Bit):END FUNCTION
' _____________________________________________________________________________

' Bitwise Stack Functions
DIM BITSTACK% = 0
DIM BITPTR = 0

FUNCTION BitPush(Val)
BitPush = (BITSTACK% << 1) OR NOT NOT Val
BitStack% = BitPush
BITPTR = BITPTR + 1
IF BITPTR > 64 THEN ERROR ("Stack Overflow")
END FUNCTION

FUNCTION BitPull()
BitPull = BitGet(BITSTACK%, 0)
BITSTACK% = (BITSTACK% >> 1)
BITPTR = BITPTR - 1
IF BITPTR < 0 THEN ERROR ("Stack Underflow")
END FUNCTION

FUNCTION BitSwap()
Bit0 = BitPull()
Bit1 = BitPull()
BitSwap = BitPush(Bit0)
BitSwap = BitPush(Bit1)
END FUNCTION

FUNCTION BitDup()
BitDup = BitPush(BitGet(BITSTACK%,0))
END FUNCTION
' _____________________________________________________________________________