Atmel ARM-Based Evaluation Kit for SAM4S16C, 32-Bit ARM® Cortex® Microcontroller ATSAM4S-WPIR-RD ATSAM4S-WPIR-RD Data Sheet
Product codes
ATSAM4S-WPIR-RD
111
SAM4S Series [DATASHEET]
Atmel-11100G-ATARM-SAM4S-Datasheet_27-May-14
When Rt is PC in a word load instruction:
Bit[0] of the loaded value 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
These instructions do not change the flags.
Examples
LDR
R0, LookUpTable
; Load R0 with a word of data from an address
; labelled as LookUpTable
LDRSB
R7, localdata
; Load a byte value from an address labelled
; as localdata, sign extend it to a word
; value, and put it in R7
12.6.4.6 LDM and STM
Load and Store Multiple registers.
Syntax
Syntax
op{addr_mode}{cond} Rn{!}, reglist
where:
opis one of:
LDMLoad Multiple registers.
STMStore Multiple registers.
addr_modeis any one of the following:
IAIncrement address After each access. This is the default.
DBDecrement address Before each access.
condis an optional condition code, see
opis one of:
LDMLoad Multiple registers.
STMStore Multiple registers.
addr_modeis any one of the following:
IAIncrement address After each access. This is the default.
DBDecrement address Before each access.
condis an optional condition code, see
.
Rnis the register on which the memory addresses are based.
!is an optional writeback suffix.
!is an optional writeback suffix.
If ! is present, the final address, that is loaded from or stored to, is written back into Rn.
reglistis a list of one or more registers to be loaded or stored, enclosed in braces. It
reglistis a list of one or more registers to be loaded or stored, enclosed in braces. It
can contain register ranges. It must be comma separated if it contains more
than one register or register range, see
.
LDM and LDMFD are synonyms for LDMIA. LDMFD refers to its use for popping data from Full Descending
stacks.
LDMEA is a synonym for LDMDB, and refers to its use for popping data from Empty Ascending stacks.
STM and STMEA are synonyms for STMIA. STMEA refers to its use for pushing data onto Empty Ascending
LDMEA is a synonym for LDMDB, and refers to its use for popping data from Empty Ascending stacks.
STM and STMEA are synonyms for STMIA. STMEA refers to its use for pushing data onto Empty Ascending
stacks.
STMFD is s synonym for STMDB, and refers to its use for pushing data onto Full Descending stacks
Operation
LDM instructions load the registers in reglist with word values from memory addresses based on Rn.
STM instructions store the word values in the registers in reglist to memory addresses based on Rn.
For LDM, LDMIA, LDMFD, STM, STMIA, and STMEA the memory addresses used for the accesses are at 4-byte
STMFD is s synonym for STMDB, and refers to its use for pushing data onto Full Descending stacks
Operation
LDM instructions load the registers in reglist with word values from memory addresses based on Rn.
STM instructions store the word values in the registers in reglist to memory addresses based on Rn.
For LDM, LDMIA, LDMFD, STM, STMIA, and STMEA the memory addresses used for the accesses are at 4-byte
intervals ranging from Rn to Rn + 4 * (n-1), where n is the number of registers in reglist. The accesses happens in