Atmel Xplained Pro Evaluation Kit ATSAM4E-XPRO ATSAM4E-XPRO Data Sheet

101

SAM4E [DATASHEET]

Atmel-11157D-ATARM-SAM4E16-SAM4E8-Datasheet_12-Jun-14

Load register from memory.

Syntax

LDR{type}{cond} Rt, label

LDRD{cond} Rt, Rt2, label

; Load two words

where:

type

is one of:

B

unsigned byte, zero extend to 32 bits.

SB

signed byte, sign extend to 32 bits.

H

unsigned halfword, zero extend to 32 bits.

SH

signed halfword, sign extend to 32 bits.

-

omit, for word.

cond

is an optional condition code, see 

.

Rt

is the register to load or store.

Rt2

is the second register to load or store.

label

is 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 

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

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

Restrictions

In these instructions:



Rt can be SP or PC only for word loads



Rt2 must not be SP and must not be PC



Rt must be different from Rt2.

Word, halfword, signed halfword, byte, signed byte

-4095 to 4095

Two words

-1020 to 1020