Atmel SAM4S-EK2 Atmel ATSAM4S-EK2 ATSAM4S-EK2 Data Sheet

 100

SAM4S [DATASHEET]

11100E–ATARM–24-Jul-13

register numbers, with the highest numbered register using the highest memory address and the lowest number register
using the lowest memory address. If the writeback suffix is specified, the value of Rn - 4 * (n-1) is written back to Rn.

The PUSH and POP instructions can be expressed in this form. See 

for details.

Restrictions

In these instructions:



Rn must not be PC



reglist must not contain SP



In any STM instruction, reglist must not contain PC



In any LDM instruction, reglist must not contain PC if it contains LR



reglist must not contain Rn if the writeback suffix is specified.

When PC is in reglist in an LDM instruction:



Bit[0] of the value loaded to the PC must be 1 for correct execution, and a branch occurs to this halfword-aligned 
address



If the instruction is conditional, it must be the last instruction in the IT block.

Condition Flags

These instructions do not change the flags.

Examples

LDM

R8,{R0,R2,R9}

; LDMIA is a synonym for LDM

STMDB

R1!,{R3-R6,R11,R12}

Incorrect Examples

STM

R5!,{R5,R4,R9} ; Value stored for R5 is unpredictable

LDM

R2, {}

; There must be at least one register in the list