module BINBCD 
title 
'comparator and binary to bcd decoder for Blackjack Machine
Michael Holley   Data I/O Corp   9 Aug 1990'

" The 5 -bit binary (0 - 31) score is converted into two BCD outputs.
" The interger division '/' and the modulus operator '%' are used to
" extract the individual digits from the two digit score.
" 'Score % 10' will yield the 'units' and
" 'Score / 10' will yield the 'tens'
"
" The 'GT16' and 'LT22' outputs are for the state machine controller.

        binbcd  device  'P16L8';

        S4,S3,S2,S1,S0  pin 5,4,3,2,1;
        score           = [S4,S3,S2,S1,S0];

        LT22,GT16       pin 12,13;

        D5,D4           pin 14,15;
        bcd2            = [D5,D4];

        D3,D2,D1,D0     pin 16,17,18,19;
        bcd1            = [D3,D2,D1,D0];

" Digit separation macros
        binary    = 0;      "scratch variable
        clear   macro (a) {@const ?a=0};
        inc     macro (a) {@const ?a=?a+1;};

equations
        LT22    = (score < 22);  "Bust
        GT16    = (score > 16);  "Hit / Stand

test_vectors ( score -> [GT16,LT22])
                 1   -> [ 0  , 1  ];
                 6   -> [ 0  , 1  ];
                 8   -> [ 0  , 1  ];
                16   -> [ 0  , 1  ];
                17   -> [ 1  , 1  ];
                18   -> [ 1  , 1  ];
                20   -> [ 1  , 1  ];
                21   -> [ 1  , 1  ];
                22   -> [ 1  , 0  ];
                23   -> [ 1  , 0  ];
                24   -> [ 1  , 0  ];
@page
truth_table ( score -> [bcd2,bcd1])
                 0  -> [  0 ,  0 ];
                 1  -> [  0 ,  1 ];
                 2  -> [  0 ,  2 ];
                 3  -> [  0 ,  3 ];
                 4  -> [  0 ,  4 ];
                 5  -> [  0 ,  5 ];
                 6  -> [  0 ,  6 ];
                 7  -> [  0 ,  7 ];
                 8  -> [  0 ,  8 ];
                 9  -> [  0 ,  9 ];
                10  -> [  1 ,  0 ];
                11  -> [  1 ,  1 ];
                12  -> [  1 ,  2 ];
                13  -> [  1 ,  3 ];
                14  -> [  1 ,  4 ];
                15  -> [  1 ,  5 ];
                16  -> [  1 ,  6 ];
                17  -> [  1 ,  7 ];
                18  -> [  1 ,  8 ];
                19  -> [  1 ,  9 ];
                20  -> [  2 ,  0 ];
                21  -> [  2 ,  1 ];
                22  -> [  2 ,  2 ];
                23  -> [  2 ,  3 ];
                24  -> [  2 ,  4 ];
                25  -> [  2 ,  5 ];
                26  -> [  2 ,  6 ];
                27  -> [  2 ,  7 ];
                28  -> [  2 ,  8 ];
                29  -> [  2 ,  9 ];
                30  -> [  3 ,  0 ];
                31  -> [  3 ,  1 ];

" This truth table could be replaced with the following macro.
"       clear(binary);
"       @repeat 32 {
"               binary -> [binary/10,binary%10]; inc(binary);}
"
" 
" The test vectors will demonstrate the use of the macro.
"
test_vectors ( score -> [bcd2,bcd1])
        clear(binary); 
        @repeat 32 {
                binary -> [binary/10,binary%10]; inc(binary);}
end