DR
AFT
DR
AFT
DRAFT
DR
D
RAFT
DRAFT
DRA
FT DRAF
D
RAFT DRAFT DRAFT DRAFT DRAFT D
DRAFT
D
RAFT DRA
FT DRAFT DRAFT DRAFT DRA
UM10360_0
© NXP B.V. 2009. All rights reserved.
User manual
Rev. 00.06 — 5 June 2009
647 of 808
NXP Semiconductors
UM10360
Chapter 34: Appendix: Cortex-M3 User Guide
2.5.1 ADD, ADC, SUB, SBC, and RSB
Add, Add with carry, Subtract, Subtract with carry, and Reverse Subtract.
2.5.1.1
Syntax
op
{S}{
cond
} {
Rd
,}
Rn
,
Operand2
op
{
cond
} {
Rd
,}
Rn
, #
imm12
; ADD and SUB only
where:
op
is one of:
ADD:
Add.
ADC:
Add with Carry.
SUB:
Subtract.
RSB:
Reverse Subtract.
S: is an optional suffix. If S is specified, the condition code flags are updated on the result
of the operation, see
Section 34–2.3.7 “Conditional execution”
cond: i
s an optional condition code, see
Section 34–2.3.7 “Conditional execution”
.
Rd
is the destination register. If
Rd
is omitted, the destination register is
Rn
.
Rn
is the register holding the first operand.
Operand2
is a flexible second operand. See
for details of the options.
imm12
is any value in the range 0-4095.
2.5.1.2
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
.
Remark:
ADDW
is equivalent to the
ADD
syntax that uses the
imm12
operand.
SUBW
is
equivalent to the
SUB
syntax that uses the
imm12
operand.
2.5.1.3
Restrictions
•
Operand2
must not be SP and must not be PC
•
Rd
can be SP only in
ADD
and
SUB
, and only with the additional restrictions: