Cortex-M3 Processor (Reference Material)
UG0331 User Guide Revision 15.0
46
3.5.5.4
External Event Input
The processor provides an external event input signal. Peripherals can drive this signal, either to wake
the processor from WFE, or to set the internal WFE event register to one to indicate that the processor
must not enter Sleep mode on a later WFE instruction. See
page 46 for more information.
3.5.5.5
Power Management Programming Hints
ISO/IEC C cannot directly generate the WFI and WFE instructions. The CMSIS provides the following
functions for these instructions:
void __WFE(void) // Wait for Event
void __WFI(void) // Wait for Interrupt
3.6
Cortex-M3 Processor Instruction Set
This section is the reference material for the Cortex-M3 processor instruction set description in this user
guide.
3.6.1
Instruction Set Summary
The processor implements a version of the Thumb instruction set. The following table lists the supported
instructions.
In the following table:
•
angle brackets, <>, enclose alternative forms of the operand
•
braces, {}, enclose optional operands
•
the Operands column is not exhaustive
•
Op2 is a flexible second operand that can be either a register or a constant
•
most instructions can use an optional condition code suffix.
For more information on the instructions and operands, see the instruction descriptions.
Table 26 •
Cortex-M3 Processor Instructions
Mnemonic
Operands
Brief description
Flags
ADC, ADCS
{Rd,} Rn, Op2
Add with Carry
N, Z, C, V
ADD, ADDS
{Rd,} Rn, Op2
Add
N, Z, C, V
ADD, ADDW
{Rd,} Rn, #imm12
Add
N, Z, C, V
ADR
Rd, label
Load PC-relative Address
AND, ANDS
{Rd,} Rn, Op2
Logical AND
N, Z, C
ASR, ASRS
Rd, Rm, <Rs|#n>
Arithmetic Shift Right
N, Z, C
B
label
Branch
BFC
Rd, #lsb, #width
Bit Field Clear
BFI
Rd, Rn, #lsb, #width
Bit Field Insert
BIC, BICS
{Rd,} Rn, Op2
Bit Clear
N, Z, C
BKPT
#imm
Breakpoint
BL
label
Branch with Link
BLX
Rm
Branch indirect with Link
BX
Rm
Branch indirect
CBNZ
Rn, label
Compare and Branch if Non Zero
CBZ
Rn, label
Compare and Branch if Zero
CLREX
Clear Exclusive