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ffa_ch1_genesis.kv      1 ------------------------------------------------------------------------------
ffa_ch1_genesis.kv      2 ------------------------------------------------------------------------------
ffa_ch1_genesis.kv      3 -- This file is part of 'Finite Field Arithmetic', aka 'FFA'.               --
ffa_ch1_genesis.kv      4 --                                                                          --
ffa_ch1_genesis.kv      5 -- (C) 2017 Stanislav Datskovskiy ( www.loper-os.org )                      --
ffa_ch1_genesis.kv      6 -- http://wot.deedbot.org/17215D118B7239507FAFED98B98228A001ABFFC7.html     --
ffa_ch1_genesis.kv      7 --                                                                          --
ffa_ch1_genesis.kv      8 -- You do not have, nor can you ever acquire the right to use, copy or      --
ffa_ch1_genesis.kv      9 -- distribute this software ; Should you use this software for any purpose, --
ffa_ch1_genesis.kv     10 -- or copy and distribute it to anyone or in any manner, you are breaking   --
ffa_ch1_genesis.kv     11 -- the laws of whatever soi-disant jurisdiction, and you promise to         --
ffa_ch1_genesis.kv     12 -- continue doing so for the indefinite future. In any case, please         --
ffa_ch1_genesis.kv     13 -- always : read and understand any software ; verify any PGP signatures    --
ffa_ch1_genesis.kv     14 -- that you use - for any purpose.                                          --
ffa_ch1_genesis.kv     15 --                                                                          --
ffa_ch1_genesis.kv     16 -- See also http://trilema.com/2015/a-new-software-licensing-paradigm .     --
ffa_ch1_genesis.kv     17 ------------------------------------------------------------------------------
ffa_ch1_genesis.kv     18 ------------------------------------------------------------------------------
ffa_ch1_genesis.kv     19 
ffa_ch1_genesis.kv     20 with Word_Ops; use Word_Ops;
ffa_ch1_genesis.kv     21 
ffa_ch1_genesis.kv     22 -- Fundamental Arithmetic operators on FZ:
ffa_ch1_genesis.kv     23 package body FZ_Arith is
ffa_ch1_genesis.kv     24    
ffa_ch1_genesis.kv     25    -- Sum := X + Y; Overflow := Carry
ffa_ch1_genesis.kv     26    procedure FZ_Add(X          : in  FZ;
ffa_ch1_genesis.kv     27                     Y          : in  FZ;
ffa_ch1_genesis.kv     28                     Sum        : out FZ;
ffa_ch1_genesis.kv     29                     Overflow   : out WBool) is
ffa_ch1_genesis.kv     30       Carry : WBool := 0;
ffa_ch1_genesis.kv     31    begin
ffa_ch1_genesis.kv     32       for i in X'Range loop
ffa_ch1_genesis.kv     33          declare
ffa_ch1_genesis.kv     34             A : constant Word := X(I);
ffa_ch1_genesis.kv     35             B : constant Word := Y(I);
ffa_ch1_genesis.kv     36             S : constant Word := A + B + Carry;
ffa_ch1_genesis.kv     37          begin
ffa_ch1_genesis.kv     38             Sum(i) := S;
ffa_ch1_genesis.kv     39             Carry  := W_Carry(A, B, S);
ffa_ch1_genesis.kv     40          end;
ffa_ch1_genesis.kv     41       end loop;
ffa_ch1_genesis.kv     42       Overflow := Carry;
ffa_ch1_genesis.kv     43    end FZ_Add;
ffa_ch1_genesis.kv     44    pragma Inline_Always(FZ_Add);
ffa_ch1_genesis.kv     45    
ffa_ch1_genesis.kv     46    
ffa_ch5_egypt.kv       47    -- Gate = 1: Sum := X + Y; Overflow := Carry
ffa_ch5_egypt.kv       48    -- Gate = 0: Sum := X;     Overflow := 0
ffa_ch5_egypt.kv       49    procedure FZ_Add_Gated_O(X          : in  FZ;
ffa_ch5_egypt.kv       50                             Y          : in  FZ;
ffa_ch5_egypt.kv       51                             Gate       : in  WBool;
ffa_ch5_egypt.kv       52                             Sum        : out FZ;
ffa_ch5_egypt.kv       53                             Overflow   : out WBool) is
ffa_ch5_egypt.kv       54       Carry : WBool := 0;
ffa_ch5_egypt.kv       55       Mask  : constant Word := 0 - Gate;
ffa_ch5_egypt.kv       56    begin
ffa_ch5_egypt.kv       57       for i in 0 .. Word_Index(X'Length - 1) loop
ffa_ch5_egypt.kv       58          declare
ffa_ch5_egypt.kv       59             A : constant Word := X(X'First + i);
ffa_ch5_egypt.kv       60             B : constant Word := Y(Y'First + i) and Mask;
ffa_ch5_egypt.kv       61             S : constant Word := A + B + Carry;
ffa_ch5_egypt.kv       62          begin
ffa_ch5_egypt.kv       63             Sum(Sum'First + i) := S;
ffa_ch5_egypt.kv       64             Carry  := W_Carry(A, B, S);
ffa_ch5_egypt.kv       65          end;
ffa_ch5_egypt.kv       66       end loop;
ffa_ch5_egypt.kv       67       Overflow := Carry;
ffa_ch5_egypt.kv       68    end FZ_Add_Gated_O;
ffa_ch5_egypt.kv       69    pragma Inline_Always(FZ_Add_Gated_O);
ffa_ch5_egypt.kv       70    
ffa_ch5_egypt.kv       71    
ffa_ch5_egypt.kv       72    -- Same as FZ_Add_Gated_O, but without Overflow output
ffa_ch5_egypt.kv       73    procedure FZ_Add_Gated(X          : in  FZ;
ffa_ch5_egypt.kv       74                           Y          : in  FZ;
ffa_ch5_egypt.kv       75                           Gate       : in  WBool;
ffa_ch5_egypt.kv       76                           Sum        : out FZ) is
ffa_ch5_egypt.kv       77       Overflow : Word;
ffa_ch5_egypt.kv       78       pragma Unreferenced(Overflow);
ffa_ch5_egypt.kv       79    begin
ffa_ch5_egypt.kv       80       FZ_Add_Gated_O(X, Y, Gate, Sum, Overflow);
ffa_ch5_egypt.kv       81    end FZ_Add_Gated;
ffa_ch5_egypt.kv       82    pragma Inline_Always(FZ_Add_Gated);
ffa_ch5_egypt.kv       83    
ffa_ch5_egypt.kv       84    
ffa_ch1_genesis.kv     85    -- Difference := X - Y; Underflow := Borrow
ffa_ch1_genesis.kv     86    procedure FZ_Sub(X          : in  FZ;
ffa_ch1_genesis.kv     87                     Y          : in  FZ;
ffa_ch1_genesis.kv     88                     Difference : out FZ;
ffa_ch1_genesis.kv     89                     Underflow  : out WBool) is
ffa_ch1_genesis.kv     90       Borrow : WBool := 0;
ffa_ch1_genesis.kv     91    begin
ffa_ch1_genesis.kv     92       for i in 0 .. Word_Index(X'Length - 1) loop
ffa_ch1_genesis.kv     93          declare
ffa_ch1_genesis.kv     94             A : constant Word := X(X'First + i);
ffa_ch1_genesis.kv     95             B : constant Word := Y(Y'First + i);
ffa_ch1_genesis.kv     96             S : constant Word := A - B - Borrow;
ffa_ch1_genesis.kv     97          begin
ffa_ch1_genesis.kv     98             Difference(Difference'First + i) := S;
ffa_ch1_genesis.kv     99             Borrow := W_Borrow(A, B, S);
ffa_ch1_genesis.kv    100          end;
ffa_ch1_genesis.kv    101       end loop;
ffa_ch1_genesis.kv    102       Underflow := Borrow;
ffa_ch1_genesis.kv    103    end FZ_Sub;
ffa_ch1_genesis.kv    104    pragma Inline_Always(FZ_Sub);
ffa_ch1_genesis.kv    105    
ffa_ch1_genesis.kv    106 end FZ_Arith;