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-- This file is part of 'Finite Field Arithmetic', aka 'FFA'.               --
--                                                                          --
-- (C) 2017 Stanislav Datskovskiy ( www.loper-os.org )                      --
-- http://wot.deedbot.org/17215D118B7239507FAFED98B98228A001ABFFC7.html     --
--                                                                          --
-- You do not have, nor can you ever acquire the right to use, copy or      --
-- distribute this software ; Should you use this software for any purpose, --
-- or copy and distribute it to anyone or in any manner, you are breaking   --
-- the laws of whatever soi-disant jurisdiction, and you promise to         --
-- continue doing so for the indefinite future. In any case, please         --
-- always : read and understand any software ; verify any PGP signatures    --
-- that you use - for any purpose.                                          --
--                                                                          --
-- See also http://trilema.com/2015/a-new-software-licensing-paradigm .     --
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with Words; use Words;
with FZ_Type; use FZ_Type;


package FZ_Basic is
   
   pragma Pure;
   
   -- Determine the Bitness of N
   function FZ_Bitness(N : in FZ) return Bit_Count;
   
   -- N := 0
   procedure FZ_Clear(N : out FZ);
   
   -- Set given FZ to a given truth value
   procedure WBool_To_FZ(V : in WBool; N : out FZ);
   
   -- First word of N := Source
   procedure FZ_Set_Head(N : out FZ; Source : in Word);
   
   -- First word of N
   function FZ_Get_Head(N : in FZ) return Word;
   
   -- Exchange X and Y
   procedure FZ_Swap(X : in out FZ; Y : in out FZ);
   pragma Precondition(X'Length = Y'Length);
   
   -- Constant-time MUX: Sel = 0: Result := X; Sel = 1: Result := Y
   procedure FZ_Mux(X : in FZ; Y : in FZ; Result : out FZ; Sel : in WBool);
   pragma Precondition(X'Length = Y'Length and X'Length = Result'Length);
   
end FZ_Basic;