DEFINITION MODULE BitByteOps ;

FROM SYSTEM IMPORT BYTE ;


(*
   GetBits - returns the bits firstBit..lastBit from source.
             Bit 0 of byte maps onto the firstBit of source.
*)

PROCEDURE GetBits (source: BYTE; firstBit, lastBit: CARDINAL) : BYTE ;


(*
   SetBits - sets bits in, byte, starting at, firstBit, and ending at,
             lastBit, with, pattern.  The bit zero of, pattern, will
             be placed into, byte, at position, firstBit.
*)

PROCEDURE SetBits (VAR byte: BYTE; firstBit, lastBit: CARDINAL;
                   pattern: BYTE) ;


(*
   ByteAnd - returns a bitwise (left AND right)
*)

PROCEDURE ByteAnd (left, right: BYTE) : BYTE ;


(*
   ByteOr - returns a bitwise (left OR right)
*)

PROCEDURE ByteOr (left, right: BYTE) : BYTE ;


(*
   ByteXor - returns a bitwise (left XOR right)
*)

PROCEDURE ByteXor (left, right: BYTE) : BYTE ;


(*
   ByteNot - returns a byte with all bits inverted.
*)

PROCEDURE ByteNot (byte: BYTE) : BYTE ;


(*
   ByteShr - returns a, byte, which has been shifted, count
             bits to the right.
*)

PROCEDURE ByteShr (byte: BYTE; count: CARDINAL) : BYTE ;


(*
   ByteShl - returns a, byte, which has been shifted, count
             bits to the left.
*)

PROCEDURE ByteShl (byte: BYTE; count: CARDINAL) : BYTE ;


(*
   ByteSar - shift byte arthemetic right.  Preserves the top
             end bit and as the value is shifted right.
*)

PROCEDURE ByteSar (byte: BYTE; count: CARDINAL) : BYTE ;


(*
   ByteRor - returns a, byte, which has been rotated, count
             bits to the right.
*)

PROCEDURE ByteRor (byte: BYTE; count: CARDINAL) : BYTE ;


(*
   ByteRol - returns a, byte, which has been rotated, count
             bits to the left.
*)

PROCEDURE ByteRol (byte: BYTE; count: CARDINAL) : BYTE ;


(*
   HighNibble - returns the top nibble only from, byte.
                The top nibble of, byte, is extracted and
                returned in the bottom nibble of the return
                value.
*)

PROCEDURE HighNibble (byte: BYTE) : BYTE ;


(*
   LowNibble - returns the low nibble only from, byte.
               The top nibble is replaced by zeros.
*)

PROCEDURE LowNibble (byte: BYTE) : BYTE ;


(*
   Swap - swaps the low and high nibbles in the, byte.
*)

PROCEDURE Swap (byte: BYTE) : BYTE ;


END BitByteOps.