ARM VERSION 1.2 - Manual (Page 118)

ARM Instruction Reference
4-8 Copyright © 2000, 2001 ARM Limited. All rights reserved. ARM DUI 0068B
FlexOffset is a flexible offset applied to the value in Rn (see Flexible offset syntax on
page 4-9).
label is a program-relative expression. See Register-relative and
program-relative expressions on page 3-23 for more information.
label must be within
±4KB of the current instruction.
! is an optional suffix. If ! is present, the address including the offset is
written back into Rn . You cannot use the ! suffix if Rn is r15.
Zero offset
The value in Rn is used as the address for the transfer.
Pre-indexed offset
The offset is applied to the value in Rn before the data transfer takes place. The result is
used as the memory address for the transfer. If the ! suffix is used, the result is written
back into Rn . Rn must not be r15 if the ! suffix is used.
Program-relative
This is an alternative version of the pre-indexed form. The assembler calculates the
offset from the PC for you, and generates a pre-indexed instruction with the PC as
Rn .
You cannot use the ! suffix.
Post-indexed offset
The value in Rn is used as the memory address for the transfer. The offset is applied to
the value in Rn after the data transfer takes place. The result is written back into Rn . Rn
must not be r15.