code: public static void ge_tobytes(byte[] s,ge_p2 h)
  {
    int[] recip = new int[10];
    int[] x = new int[10];
    int[] y = new int[10];
  
    fe_invert.fe_invert(recip,h.Z);
    fe_mul.fe_mul(x,h.X,recip);
    fe_mul.fe_mul(y,h.Y,recip);
    fe_tobytes.fe_tobytes(s,y);
    s[31] ^= fe_isnegative.fe_isnegative(x) << 7;
  }
docs: CONVERT #include "ge.h"