Atmel ARM-Based Evaluation Kit for SAM4S16C, 32-Bit ARM® Cortex® Microcontroller ATSAM4S-WPIR-RD ATSAM4S-WPIR-RD Data Sheet

SAM4S Series [DATASHEET]

Atmel-11100G-ATARM-SAM4S-Datasheet_27-May-14

110

Load register from memory.
Syntax

LDR{type}{cond} Rt, label

LDRD{cond} Rt, Rt2, label

; Load two words

where:
typeis one of:
Bunsigned byte, zero extend to 32 bits.
SBsigned byte, sign extend to 32 bits.
Hunsigned halfword, zero extend to 32 bits.
SHsigned halfword, sign extend to 32 bits.
-omit, for word.
condis an optional condition code, see 

.

Rtis the register to load or store.
Rt2is the second register to load or store.
labelis a PC-relative expression. See 

Operation
LDR loads a register with a value from a PC-relative memory address. The memory address is specified by a label 

or by an offset from the PC.
The value to load or store can be a byte, halfword, or word. For load instructions, bytes and halfwords can either 

be signed or unsigned. See 

.

 must be within a limited range of the current instruction. The table below shows the possible offsets between 

 and the PC.

 

The user might have to use the .W suffix to get the maximum offset range. See 

.

Restrictions
In these instructions:



 can be SP or PC only for word loads



 must not be SP and must not be PC



 must be different from Rt2.

Word, halfword, signed halfword, byte, signed byte

-4095 to 4095

Two words

-1020 to 1020