IBM AT 5170 Technical Reference page 375

Register
OlOOOreg
SUB
=
Subtract
Register/Memory with Register to Either
OOlOlOdw mod reg rim
Immediate from Register/Memory
100000sw modlOl rim data data if sw 01
Immediate from Accumulator
OOlOllOw data data if w
SBB
=
Subtract with Borrow
Register/Memory with Register to Either
OOOllOdw mod reg rim
Immediate to Register/Memory
100000sw modOll rim data data if sw 01
Immediate to Accumulator
OOOlllOw data
data if w
DEC
=
Decrement
Register/Memory
lllllllw modOOl rim
Register
OlOOlreg
CMP
=
Compare
Register/Memory with Register
OOlllOlw mod reg rim
Instruction Set 6-7