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+ 81A4BF46ABD4B92F58B791872C94193606E9847F7C232AA604F91B71412F0B9732D23BE295810596355B68B8111EF5102BB7778DCB2FE987C948490A95B49CCD
ffa/libffa/words.ads
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1030 ------------------------------------------------------------------------------
1031 ------------------------------------------------------------------------------
1032 -- This file is part of 'Finite Field Arithmetic', aka 'FFA'.               --
1033 --                                                                          --
1034 -- (C) 2017 Stanislav Datskovskiy ( www.loper-os.org )                      --
1035 -- http://wot.deedbot.org/17215D118B7239507FAFED98B98228A001ABFFC7.html     --
1036 --                                                                          --
1037 -- You do not have, nor can you ever acquire the right to use, copy or      --
1038 -- distribute this software ; Should you use this software for any purpose, --
1039 -- or copy and distribute it to anyone or in any manner, you are breaking   --
1040 -- the laws of whatever soi-disant jurisdiction, and you promise to         --
1041 -- continue doing so for the indefinite future. In any case, please         --
1042 -- always : read and understand any software ; verify any PGP signatures    --
1043 -- that you use - for any purpose.                                          --
1044 --                                                                          --
1045 -- See also http://trilema.com/2015/a-new-software-licensing-paradigm .     --
1046 ------------------------------------------------------------------------------
1047 ------------------------------------------------------------------------------
1048 
1049 with Iron;
1050 
1051 package Words is
1052    
1053    pragma Pure;
1054    
1055    -- The most fundamental fact about Word: width.
1056    Bitness     : constant Positive := Iron.MachineBitness;
1057    
1058    -- It is possible to calculate BitnessLog2 at elaboration time,
1059    -- but we will avoid having ~any~ elaboration at all in FFA.
1060    BitnessLog2 : constant Positive := Iron.MachineBitnessLog2;
1061    
1062    -- The Word width, expressed in ~bytes~:
1063    Byteness    : constant Positive := Bitness / Iron.ByteBits;
1064    
1065    -- What kind of words to use. Must be machine-word or smaller.
1066    type Word is mod 2**Bitness;
1067    for Word'Size use Bitness;
1068    
1069    -- The very same Word, but its only legal values are 0 and 1.
1070    subtype WBool is Word range 0 .. 1;
1071    
1072    -- When we must refer to individual bit positions of a machine word:
1073    subtype WBit_Index is Natural range 0 .. Bitness - 1;
1074    
1075 end Words;