module PRIOR15 
title '15-Input Priority Encoder 
J. Wakerly, DAVID Systems, Inc.' 
"PRIOR15 device 'P20L8'; 

" Input pins
P0, P1, P2, P3, P4, P5, P6, P7     pin 1, 2, 3, 4, 5, 6, 7, 8; 
P8, P9, P10, P11, P12, P13, P14    pin 9, 10, 11, 13, 14, 23, 16; 
!EN                                pin 17;

" Output pins
!Y3, !Y2, !Y1, !Y0                 pin 18, 19, 20, 21 istype 'com'; 
GS, !ENOUT                         pin 15, 22         istype 'com';

" Constant expressions
H14 = EN&P14; 
H13 = EN&!P14&P13; 
H12 = EN&!P14&!P13&P12; 
H11 = EN&!P14&!P13&!P12&P11; 
H10 = EN&!P14&!P13&!P12&!P11&P10; 
H9  = EN&!P14&!P13&!P12&!P11&!P10&P9; 
H8  = EN&!P14&!P13&!P12&!P11&!P10&!P9&P8; 
H7  = EN&!P14&!P13&!P12&!P11&!P10&!P9&!P8&P7; 
H6  = EN&!P14&!P13&!P12&!P11&!P10&!P9&!P8&!P7&P6; 
H5  = EN&!P14&!P13&!P12&!P11&!P10&!P9&!P8&!P7&!P6&P5; 
H4  = EN&!P14&!P13&!P12&!P11&!P10&!P9&!P8&!P7&!P6&!P5&P4; 
H3  = EN&!P14&!P13&!P12&!P11&!P10&!P9&!P8&!P7&!P6&!P5&!P4&P3; 
H2  = EN&!P14&!P13&!P12&!P11&!P10&!P9&!P8&!P7&!P6&!P5&!P4&!P3&P2; 
H1  = EN&!P14&!P13&!P12&!P11&!P10&!P9&!P8&!P7&!P6&!P5&!P4&!P3&!P2&P1;
H0  = EN&!P14&!P13&!P12&!P11&!P10&!P9&!P8&!P7&!P6&!P5&!P4&!P3&!P2&!P1&P0;

equations

Y3 = H8 # H9 # H10 # H11 # H12 # H13 # H14; 
Y2 = H4 # H5 # H6 # H7 # H12 # H13 # H14; 
Y1 = H2 # H3 # H6 # H7 # H10 # H11 # H14; 
Y0 = H1 # H3 # H5 # H7 # H9 # H11 # H13;

GS    = EN&(P14#P13#P12#P11#P10#P9#P8#P7#P6#P5#P4#P3#P2#P1#P0);
ENOUT = EN&!P14&!P13&!P12&!P11&!P10&!P9&!P8&!P7&!P6&!P5&!P4&!P3&!P2&!P1&!P0;

end PRIOR15