ARM Architecture Reference Manual ARMv7-A and ARMv7-R edition

Assembler syntax
STMIB {!},
where:
See Standard assembler syntax fields on page A8-7.
The base register. The SP can be used.
! Causes the instruction to write a modified value back to . Encoded as W = 1.
Instruction Details
If ! is omitted, the instruction does not change in this way. Encoded as W = 0.
Is a list of one or more registers to be stored, separated by commas and surrounded by
{ and }. The lowest-numbered register is stored to the lowest memory address, through to
the highest-numbered register to the highest memory address.
The SP and PC can be in the list. However, instructions that include the SP or the PC in the
list are deprecated.
The use of instructions with the base register in the list and ! specified is deprecated. If the
base register is not the lowest-numbered register in the list, such an instruction stores an
UNKNOWN value for the base register.
STMFA is a pseudo-instruction for STMIB, referring to its use for pushing data onto Full Ascending stacks.
The pre-UAL syntax STMIB and STMFA are equivalent to STMIB.
Operation
if ConditionPassed() then
EncodingSpecificOperations();
address = R[n] + 4;
for i = 0 to 14
if registers == ‘1’ then
if i == n && wback && i != LowestSetBit(registers) then
MemA[address,4] = bits(32) UNKNOWN;
else
MemA[address,4] = R[i];
address = address + 4;
if registers == ‘1’ then
MemA[address,4] = PCStoreValue();
if wback then R[n] = R[n] + 4*BitCount(registers);
Exceptions
Data Abort.
ARM DDI 0406B Copyright © 1996-1998, 2000, 2004-2008 ARM Limited. All rights reserved. A8-381