$$ zero $-1$ if R$[$rs$1]-$ R$[$rs$2]=0,0$ otherwise

$$ lt $-1$ if R$[$rs$1]<$ R$[$rs$2],0$ otherwise

$$ opcode $(2$b$)-00$: blt $(<),01$: bge $(>=),$

$10$: beq $(==),11$: bne $(!=)$

Output:

$$ branch $-1$ if branch should be taken, $0$ if not