module BLOCK (BIT, OCTET) is

type Block is
   !implementedby "BLOCK"
   !printedby "PRINT_BLOCK"
   Block (O1, O2, O3, O4 : Octet) !implementedby "BUILD_BLOCK"
   with get, == !implementedby "EQUAL_BLOCK", !=
end type

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function AND (X, Y : Block) : Block is
   return Block (X.O1 and Y.O1, X.O2 and Y.O2, X.O3 and Y.O3, X.O4 and Y.O4)
end function

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function OR (X, Y : Block) : Block is
   return Block (X.O1 or Y.O1, X.O2 or Y.O2, X.O3 or Y.O3, X.O4 or Y.O4)
end function

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function XOR (X, Y : Block) : Block is
   return Block (X.O1 xor Y.O1, X.O2 xor Y.O2, X.O3 xor Y.O3, X.O4 xor Y.O4)
end function

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function CYC (X : Block) : Block is
   return Block (
      Octet (X.O1.B2, X.O1.B3, X.O1.B4, X.O1.B5, X.O1.B6, X.O1.B7, X.O1.B8, X.O2.B1),
      Octet (X.O2.B2, X.O2.B3, X.O2.B4, X.O2.B5, X.O2.B6, X.O2.B7, X.O2.B8, X.O3.B1),
      Octet (X.O3.B2, X.O3.B3, X.O3.B4, X.O3.B5, X.O3.B6, X.O3.B7, X.O3.B8, X.O4.B1),
      Octet (X.O4.B2, X.O4.B3, X.O4.B4, X.O4.B5, X.O4.B6, X.O4.B7, X.O4.B8, X.O1.B1))
end function

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function ADD (X, Y : Block) : Block is
   -- sum modulo 2^32 of X and Y
   !implementedby "ADD"
   !external
   null
end function

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function CAR (X, Y : Block) : Block is
   -- carry of the sum of X and Y, result being either x00000000 or x00000001
   !implementedby "CAR"
   !external
   null
end function

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function HIGH_MUL (X, Y : Block) : Block is
   -- 32 most significant bits of the product of X and Y
   !implementedby "HIGH_MUL"
   !external
   null
end function

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function LOW_MUL (X, Y : Block) : Block is
   -- 32 least significant bits of the product of X and Y
   !implementedby "LOW_MUL"
   !external
   null
end function

-------------------------------------------------------------------------------

end module