Sums or And (thats why SORA <- S OR A <- Sum OR And)
When 11 bit (right most bit has position 00) of microcode is set to:
ADD: 0000 0000 0001 0000 1110 0000 1001 0000 0001 0001
^
AND: 0000 0000 0001 0000 1100 0000 1001 1000 0001 0001
^
0
-- SUM sums operands on right and left ALU inputs1
-- AND computes logical AND from right and left ALU inputs