1 ltorg – ARM VERSION 1.2 User Manual

Page 296

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Directives Reference

7-14

Copyright © 2000, 2001 ARM Limited. All rights reserved.

ARM DUI 0068B

7.3.1

LTORG

The

LTORG

directive instructs the assembler to assemble the current literal pool

immediately.

Syntax

LTORG

Usage

The assembler assembles the current literal pool at the end of every code section. The
end of a code section is determined by the

AREA

directive at the beginning of the

following section, or the end of the assembly.

These default literal pools can sometimes be out of range of some

LDR

,

LDFD

, and

LDFS

pseudo-instructions. See LDR ARM pseudo-instruction on page 4-82 and LDR Thumb
pseudo-instruction
on page 5-41 for
more information. Use

LTORG

to ensure that a literal

pool is assembled within range. Large programs can require several literal pools.

Place

LTORG

directives after unconditional branches or subroutine return instructions so

that the processor does not attempt to execute the constants as instructions.

The assembler word-aligns data in literal pools.

Example

AREA Example, CODE, READONLY
start BL func1

func1 ; function body
; code
LDR r1,=0x55555555 ; => LDR R1, [pc, #offset to Literal Pool 1]
; code
MOV pc,lr ; end function
LTORG ; Literal Pool 1 contains literal &55555555.

data SPACE 4200 ; Clears 4200 bytes of memory,
; starting at current location.
END ; Default literal pool is empty.

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