ARM VERSION 1.2 Computer Hardware User Manual


 
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.