bit T, H
bit[4] L4
bit[3] H3
{AC, L4} = A[3:0] + R[3:0] + C
{T, H3} = A[6:4] + R[6:4] + AC
{C, H} = A[7] + R[7] + T
OV = C ^ T
A = {H, H3, L4}
Z = A ? 0 : 1
bit T, H
bit[4] L4
bit[3] H3
{AC, L4} = A[3:0] + R[3:0] + C
{T, H3} = A[6:4] + R[6:4] + AC
{C, H} = A[7] + R[7] + T
OV = C ^ T
R = {H, H3, L4}
Z = R ? 0 : 1