2.6.5.5.2 Operation

These instructions compare the value in a register with Operand2. They update the condition flags on the result, but do not write the result to a register.

The CMP instruction subtracts the value of Operand2 from the value in Rn. This is the same as a SUBS instruction, except that the result is discarded.

The CMN instruction adds the value of Operand2 to the value in Rn. This is the same as an ADDS instruction, except that the result is discarded.