ARM VERSION 1.2 - Manual (Page 53)

Writing ARM and Thumb Assembly Language
ARM DUI 0068B Copyright © 2000, 2001 ARM Limited. All rights reserved. 2-41
Usage
See Implementing stacks with LDM and STM on page 2-42 and Block copy with LDM
and STM on page 2-44.
2.8.2 LDM and STM addressing modes
There are four different addressing modes. The base register can be incremented or
decremented by one word for each register in the operation, and the increment or
decrement can occur before or after the operation. The suffixes for these options are:
IA Increment after.
IB Increment before.
DA Decrement after.
DB Decrement before.
There are alternative addressing mode suffixes that are easier to use for stack operations.
See Implementing stacks with LDM and STM on page 2-42.