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ffa_ch3_shifts.kv       1 ------------------------------------------------------------------------------
ffa_ch3_shifts.kv       2 ------------------------------------------------------------------------------
ffa_ch3_shifts.kv       3 -- This file is part of 'Finite Field Arithmetic', aka 'FFA'.               --
ffa_ch3_shifts.kv       4 --                                                                          --
ffa_ch3_shifts.kv       5 -- (C) 2017 Stanislav Datskovskiy ( www.loper-os.org )                      --
ffa_ch3_shifts.kv       6 -- http://wot.deedbot.org/17215D118B7239507FAFED98B98228A001ABFFC7.html     --
ffa_ch3_shifts.kv       7 --                                                                          --
ffa_ch3_shifts.kv       8 -- You do not have, nor can you ever acquire the right to use, copy or      --
ffa_ch3_shifts.kv       9 -- distribute this software ; Should you use this software for any purpose, --
ffa_ch3_shifts.kv      10 -- or copy and distribute it to anyone or in any manner, you are breaking   --
ffa_ch3_shifts.kv      11 -- the laws of whatever soi-disant jurisdiction, and you promise to         --
ffa_ch3_shifts.kv      12 -- continue doing so for the indefinite future. In any case, please         --
ffa_ch3_shifts.kv      13 -- always : read and understand any software ; verify any PGP signatures    --
ffa_ch3_shifts.kv      14 -- that you use - for any purpose.                                          --
ffa_ch3_shifts.kv      15 --                                                                          --
ffa_ch3_shifts.kv      16 -- See also http://trilema.com/2015/a-new-software-licensing-paradigm .     --
ffa_ch3_shifts.kv      17 ------------------------------------------------------------------------------
ffa_ch3_shifts.kv      18 ------------------------------------------------------------------------------
ffa_ch3_shifts.kv      19 
ffa_ch2_logicals.kv    20 with Word_Ops; use Word_Ops;
ffa_ch2_logicals.kv    21 
ffa_ch2_logicals.kv    22 
ffa_ch2_logicals.kv    23 package body FZ_Basic is
ffa_ch2_logicals.kv    24    
ffa_ch2_logicals.kv    25    ---------------------------------------------------------------------------
ffa_ch2_logicals.kv    26    -- Fundamental Operations on FZ (finite integers)
ffa_ch2_logicals.kv    27    ---------------------------------------------------------------------------
ffa_ch2_logicals.kv    28    
ffa_ch5_egypt.kv       29    -- Determine the Bitness of N
ffa_ch5_egypt.kv       30    function FZ_Bitness(N : in FZ) return Bit_Count is
ffa_ch5_egypt.kv       31    begin
ffa_ch5_egypt.kv       32       return N'Length * Words.Bitness;
ffa_ch5_egypt.kv       33    end FZ_Bitness;
ffa_ch5_egypt.kv       34    
ffa_ch5_egypt.kv       35    
ffa_ch2_logicals.kv    36    -- N := 0
ffa_ch2_logicals.kv    37    procedure FZ_Clear(N : out FZ) is
ffa_ch2_logicals.kv    38    begin
ffa_ch2_logicals.kv    39       N := (others => 0);
ffa_ch2_logicals.kv    40    end FZ_Clear;
ffa_ch2_logicals.kv    41    
ffa_ch2_logicals.kv    42    
ffa_ch4_ffacalc.kv     43    -- Set given FZ to a given truth value
ffa_ch4_ffacalc.kv     44    procedure WBool_To_FZ(V : in WBool; N : out FZ) is
ffa_ch4_ffacalc.kv     45    begin
ffa_ch4_ffacalc.kv     46       FZ_Clear(N);
ffa_ch4_ffacalc.kv     47       FZ_Set_Head(N, V);
ffa_ch4_ffacalc.kv     48    end WBool_To_FZ;
ffa_ch4_ffacalc.kv     49    
ffa_ch4_ffacalc.kv     50    
ffa_ch2_logicals.kv    51    -- First word of N := Source
ffa_ch2_logicals.kv    52    procedure FZ_Set_Head(N : out FZ; Source : in Word) is
ffa_ch2_logicals.kv    53    begin
ffa_ch2_logicals.kv    54       N(N'First) := Source;
ffa_ch2_logicals.kv    55    end FZ_Set_Head;
ffa_ch2_logicals.kv    56    
ffa_ch2_logicals.kv    57    
ffa_ch2_logicals.kv    58    -- First word of N
ffa_ch2_logicals.kv    59    function FZ_Get_Head(N : in FZ) return Word is
ffa_ch2_logicals.kv    60    begin
ffa_ch2_logicals.kv    61       return N(N'First);
ffa_ch2_logicals.kv    62    end FZ_Get_Head;
ffa_ch2_logicals.kv    63    
ffa_ch2_logicals.kv    64    
ffa_ch2_logicals.kv    65    -- Exchange X and Y
ffa_ch2_logicals.kv    66    procedure FZ_Swap(X : in out FZ; Y : in out FZ) is
ffa_ch3_shifts.kv      67       T : FZ(X'Range);
ffa_ch2_logicals.kv    68    begin
ffa_ch2_logicals.kv    69       T := X;
ffa_ch2_logicals.kv    70       X := Y;
ffa_ch2_logicals.kv    71       Y := T;
ffa_ch2_logicals.kv    72    end FZ_Swap;
ffa_ch2_logicals.kv    73    
ffa_ch2_logicals.kv    74    
ffa_ch2_logicals.kv    75    -- Constant-time MUX: Sel = 0: Result := X; Sel = 1: Result := Y
ffa_ch2_logicals.kv    76    procedure FZ_Mux(X : in FZ; Y : in FZ; Result : out FZ; Sel : in WBool) is
ffa_ch2_logicals.kv    77    begin
ffa_ch2_logicals.kv    78       for i in X'Range loop
ffa_ch2_logicals.kv    79          Result(i) := W_Mux(X(i), Y(i), Sel);
ffa_ch2_logicals.kv    80       end loop;
ffa_ch2_logicals.kv    81    end FZ_Mux;
ffa_ch2_logicals.kv    82    
ffa_ch2_logicals.kv    83 end FZ_Basic;