// ************************************************************************** //
//                                                                            //
//    eses                   eses                                             //
//   eses                     eses                                            //
//  eses    eseses  esesese    eses   Embedded Systems Group                  //
//  ese    ese  ese ese         ese                                           //
//  ese    eseseses eseseses    ese   Department of Computer Science          //
//  eses   eses          ese   eses                                           //
//   eses   eseses  eseseses  eses    University of Kaiserslautern            //
//    eses                   eses                                             //
//                                                                            //
// ************************************************************************** //


[16]nat x;
[16]nat y;
[17]nat s;

thread RadixBAddCarryLookahead16 {
    [16]bool g;
    [16]bool p;
    // preliminary sum digits
    s[0] = x[0] + y[0];
    s[1] = x[1] + y[1];
    s[2] = x[2] + y[2];
    s[3] = x[3] + y[3];
    s[4] = x[4] + y[4];
    s[5] = x[5] + y[5];
    s[6] = x[6] + y[6];
    s[7] = x[7] + y[7];
    s[8] = x[8] + y[8];
    s[9] = x[9] + y[9];
    s[10] = x[10] + y[10];
    s[11] = x[11] + y[11];
    s[12] = x[12] + y[12];
    s[13] = x[13] + y[13];
    s[14] = x[14] + y[14];
    s[15] = x[15] + y[15];
    // initial generate conditions
    g[0] = s[0]>255;
    g[1] = s[1]>255;
    g[2] = s[2]>255;
    g[3] = s[3]>255;
    g[4] = s[4]>255;
    g[5] = s[5]>255;
    g[6] = s[6]>255;
    g[7] = s[7]>255;
    g[8] = s[8]>255;
    g[9] = s[9]>255;
    g[10] = s[10]>255;
    g[11] = s[11]>255;
    g[12] = s[12]>255;
    g[13] = s[13]>255;
    g[14] = s[14]>255;
    g[15] = s[15]>255;
    // initial propagate conditions
    p[0] = s[0]==255;
    p[1] = s[1]==255;
    p[2] = s[2]==255;
    p[3] = s[3]==255;
    p[4] = s[4]==255;
    p[5] = s[5]==255;
    p[6] = s[6]==255;
    p[7] = s[7]==255;
    p[8] = s[8]==255;
    p[9] = s[9]==255;
    p[10] = s[10]==255;
    p[11] = s[11]==255;
    p[12] = s[12]==255;
    p[13] = s[13]==255;
    p[14] = s[14]==255;
    p[15] = s[15]==255;
    // carry propagation prefix tree
    // up-level 1
    g[1] = g[0] & p[1] | g[1];
    p[1] = p[1] & p[0];
    g[3] = g[2] & p[3] | g[3];
    p[3] = p[3] & p[2];
    g[5] = g[4] & p[5] | g[5];
    p[5] = p[5] & p[4];
    g[7] = g[6] & p[7] | g[7];
    p[7] = p[7] & p[6];
    g[9] = g[8] & p[9] | g[9];
    p[9] = p[9] & p[8];
    g[11] = g[10] & p[11] | g[11];
    p[11] = p[11] & p[10];
    g[13] = g[12] & p[13] | g[13];
    p[13] = p[13] & p[12];
    g[15] = g[14] & p[15] | g[15];
    p[15] = p[15] & p[14];
    // up-level 2
    g[3] = g[1] & p[3] | g[3];
    p[3] = p[3] & p[1];
    g[7] = g[5] & p[7] | g[7];
    p[7] = p[7] & p[5];
    g[11] = g[9] & p[11] | g[11];
    p[11] = p[11] & p[9];
    g[15] = g[13] & p[15] | g[15];
    p[15] = p[15] & p[13];
    // up-level 3
    g[7] = g[3] & p[7] | g[7];
    p[7] = p[7] & p[3];
    g[15] = g[11] & p[15] | g[15];
    p[15] = p[15] & p[11];
    // up-level 4
    g[15] = g[7] & p[15] | g[15];
    p[15] = p[15] & p[7];
    // down-level 6
    // down-level 7
    g[11] = g[7] & p[11] | g[11];
    p[11] = p[11] & p[7];
    // down-level 8
    g[5] = g[3] & p[5] | g[5];
    p[5] = p[5] & p[3];
    g[9] = g[7] & p[9] | g[9];
    p[9] = p[9] & p[7];
    g[13] = g[11] & p[13] | g[13];
    p[13] = p[13] & p[11];
    // down-level 9
    g[2] = g[1] & p[2] | g[2];
    p[2] = p[2] & p[1];
    g[4] = g[3] & p[4] | g[4];
    p[4] = p[4] & p[3];
    g[6] = g[5] & p[6] | g[6];
    p[6] = p[6] & p[5];
    g[8] = g[7] & p[8] | g[8];
    p[8] = p[8] & p[7];
    g[10] = g[9] & p[10] | g[10];
    p[10] = p[10] & p[9];
    g[12] = g[11] & p[12] | g[12];
    p[12] = p[12] & p[11];
    g[14] = g[13] & p[14] | g[14];
    p[14] = p[14] & p[13];
    // compute final sum digits
    s[0] = s[0] % 256;
    s[1] = (s[1]+(g[0]?1:0)) % 256;
    s[2] = (s[2]+(g[1]?1:0)) % 256;
    s[3] = (s[3]+(g[2]?1:0)) % 256;
    s[4] = (s[4]+(g[3]?1:0)) % 256;
    s[5] = (s[5]+(g[4]?1:0)) % 256;
    s[6] = (s[6]+(g[5]?1:0)) % 256;
    s[7] = (s[7]+(g[6]?1:0)) % 256;
    s[8] = (s[8]+(g[7]?1:0)) % 256;
    s[9] = (s[9]+(g[8]?1:0)) % 256;
    s[10] = (s[10]+(g[9]?1:0)) % 256;
    s[11] = (s[11]+(g[10]?1:0)) % 256;
    s[12] = (s[12]+(g[11]?1:0)) % 256;
    s[13] = (s[13]+(g[12]?1:0)) % 256;
    s[14] = (s[14]+(g[13]?1:0)) % 256;
    s[15] = (s[15]+(g[14]?1:0)) % 256;
    s[16] = (g[15]?1:0);
}