ARM VERSION 1.2 - page 128

ARM Instruction Reference
4-18 Copyright © 2000, 2001 ARM Limited. A ll rights reserved. ARM DUI 0068B
4.2.4 LDM and STM
Load and store multiple registers. Any combination of registers r0 to r15 can be
transferred.
Syntax
op{cond}mode Rn{!}, reglist{^}
where:
op is either LDM or STM .
cond is an optional condition code (see Conditional execution on page4-4).
mode is any one of the following:
IA increment address after each transfer
IB increment address before each transfer
DA decrement address after each transfer
DB decrement address before each transfer
FD full descending stack
ED empty descending stack
FA full ascending stack
EA empty ascending stac k.
Rn is the base register, the ARM register containing the initial address for the
transfer.
Rn must not be r15.
! is an optional suffix. If ! is present, the final address is written back into
Rn .
reglist is a list of registers to be loaded or store d, enclosed in braces . It can
contain register ranges. It must be comma separated if it contains more
than one register or register range (see Examples on page4-19).
^ is an optional suffix. You must not use it in User mode or System mode.
It has two purposes:
•If
op is LDM and reglist contains the pc (r15), in addition to the
normal multiple regist er transfer, the
SPSR is copied into the CPSR .
This is for returning from exception handlers. Use this only from
exception modes.
•Otherwise, data is transferred into or out of the User mode registers
instead of the current mode registers.