gm2-libs-log/BitWordOps (The GNU Modula-2 Compiler)

#### 4.2.3 gm2-libs-log/BitWordOps ¶

    DEFINITION MODULE BitWordOps ;

    FROM SYSTEM IMPORT WORD ;

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

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

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

    PROCEDURE SetBits (VAR word: WORD; firstBit, lastBit: CARDINAL;
                       pattern: WORD) ;

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

    PROCEDURE WordAnd (left, right: WORD) : WORD ;

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

    PROCEDURE WordOr (left, right: WORD) : WORD ;

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

    PROCEDURE WordXor (left, right: WORD) : WORD ;

    (*
       WordNot - returns a word with all bits inverted.
    *)

    PROCEDURE WordNot (word: WORD) : WORD ;

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

    PROCEDURE WordShr (word: WORD; count: CARDINAL) : WORD ;

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

    PROCEDURE WordShl (word: WORD; count: CARDINAL) : WORD ;

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

    PROCEDURE WordSar (word: WORD; count: CARDINAL) : WORD ;

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

    PROCEDURE WordRor (word: WORD; count: CARDINAL) : WORD ;

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

    PROCEDURE WordRol (word: WORD; count: CARDINAL) : WORD ;

    (*
       HighByte - returns the top byte only from, word.
                  The byte is returned in the bottom byte
                  in the return value.
    *)

    PROCEDURE HighByte (word: WORD) : WORD ;

    (*
       LowByte - returns the low byte only from, word.
                 The byte is returned in the bottom byte
                 in the return value.
    *)

    PROCEDURE LowByte (word: WORD) : WORD ;

    (*
       Swap - byte flips the contents of word.
    *)

    PROCEDURE Swap (word: WORD) : WORD ;

    END BitWordOps.