if the following are true:

• the instruction at computer c and index i = an add instruction with dst: d src1: s1 and src2: s2
• the PC at computer c and time t = i

then byte at ID: c, cell #d at time (t + 1) = (byte at ID: c, cell #s1 at time t) + (byte at ID: c, cell #s2 at time t)