Datasheet
UM10398 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2014. All rights reserved.
User manual Rev. 12.3 — 10 June 2014 486 of 547
NXP Semiconductors
UM10398
Chapter 28: LPC111x/LPC11Cxx Appendix: ARM Cortex-M0 reference
• the value in the register specified by Rn must be word aligned. See
Section 28–28.5.3.4
for more information.
• for STM, if Rn appears in reglist, then it must be the first register in the list.
28.5.4.5.4 Condition flags
These instructions do not change the flags.
28.5.4.5.5 Examples
LDM R0,{R0,R3,R4} ; LDMIA is a synonym for LDM
STMIA R1!,{R2-R4,R6}
28.5.4.5.6 Incorrect examples
STM R5!,{R4,R5,R6} ; Value stored for R5 is unpredictable
LDM R2,{} ; There must be at least one register in the list
28.5.4.6 PUSH and POP
Push registers onto, and pop registers off a full-descending stack.
28.5.4.6.1 Syntax
PUSH reglist
POP reglist
where:
reglist is a non-empty list of registers, enclosed in braces. It can contain register ranges.
It must be comma separated if it contains more than one register or register range.
28.5.4.6.2 Operation
PUSH stores registers on the stack, with the lowest numbered register using the lowest
memory address and the highest numbered register using the highest memory address.
POP loads registers from the stack, with the lowest numbered register using the lowest
memory address and the highest numbered register using the highest memory address.
PUSH uses the value in the SP register minus four as the highest memory address,
POP uses the value in the SP register as the lowest memory address, implementing a
full-descending stack. On completion,
PUSH updates the SP register to point to the location of the lowest store value,
POP updates the SP register to point to the location above the highest location loaded.
If a POP instruction includes PC in its reglist, a branch to this location is performed when
the POP instruction has completed. Bit[0] of the value read for the PC is used to update
the APSR T-bit. This bit must be 1 to ensure correct operation.
28.5.4.6.3 Restrictions
In these instructions:
• reglist must use only R0-R7.