2.6.5.1.2 Operation
The ADD instruction adds the value of Operand2 or
imm12 to the value in Rn.
The ADC instruction adds the values in
Rn and Operand2, together with the carry flag.
The SUB instruction subtracts the value of Operand2 or
imm12 from the value in Rn.
The SBC instruction subtracts the value of Operand2 from
the value in Rn. If the carry flag is clear, the result is reduced by
one.
The RSB instruction subtracts the value in
Rn from the value of Operand2. This is useful because of the wide range
of options for Operand2.
Use ADC and SBC to synthesize multiword
arithmetic, see 2.6.5.1.5 Multiword Arithmetic Examples.
See also 2.6.4.1 ADR.
Important:
ADDW is equivalent to the
ADD syntax that uses the imm12 operand.
SUBW is equivalent to the SUB syntax that uses the
imm12 operand.