103
11100B–ATARM–31-Jul-12
SAM4S Series [Preliminary]
The accesses happen in order of decreasing register numbers, with the highest numbered regis-
ter using the highest memory address and the lowest number register using the lowest memory
address. If the writeback suffix is specified, the value of Rn - 4 * (n-1) is written back to Rn.
The PUSH and POP instructions can be expressed in this form. See
details.
Restrictions
In these instructions:
• Rn must not be PC
• reglist must not contain SP
• in any STM instruction, reglist must not contain PC
• in any LDM instruction, reglist must not contain PC if it contains LR
• reglist must not contain Rn if the writeback suffix is specified.
When PC is in reglist in an LDM instruction:
• bit[0] of the value loaded to the PC must be 1 for correct execution, and a branch occurs to
this halfword-aligned address
• if the instruction is conditional, it must be the last instruction in the IT block.
Condition Flags
These instructions do not change the flags.
Examples
LDM
R8,{R0,R2,R9}
; LDMIA is a synonym for LDM
STMDB
R1!,{R3-R6,R11,R12}
Incorrect examples
STM
R5!,{R5,R4,R9} ; Value stored for R5 is unpredictable
LDM
R2, {}
; There must be at least one register in the list
Summary of Contents for SAM4S Series
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