(* BitByteOps.def provides a Logitech-3.0 compatible library.

Copyright (C) 2007-2025 Free Software Foundation, Inc.
Contributed by Gaius Mulley <gaius.mulley@southwales.ac.uk>.

This file is part of GNU Modula-2.

GNU Modula-2 is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.

GNU Modula-2 is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.

You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
<http://www.gnu.org/licenses/>.  *)

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.
