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Directives Reference
ARM DUI 0068B Copyright © 2000, 2001 ARM Limited. All rights reserved. 7-19
7.3.6 DCD and DCDU
The
DCD
directive allocates one or more words of memory, aligned on 4-byte boundaries,
and defines the initial runtime contents of the memory.
&
is a synonym for
DCD
.
DCDU
is the same, except that the memory alignment is arbitrary.
Syntax
{label} DCD{U} expr{,expr}
where:
expr
is either:
• a numeric expression (see Numeric expressions on page 3-20).
• a program-relative expression.
Usage
DCD
inserts up to 3 bytes of padding before the first defined word, if necessary, to achieve
4-byte alignment.
Use
DCDU
if you do not require alignment.
See also:
• DCB on page 7-18
• DCW and DCWU on page 7-25
• DCQ and DCQU on page 7-24
• SPACE on page 7-17.
Examples
data1 DCD 1,5,20 ; Defines 3 words containing
; decimal values 1, 5, and 20
data2 DCD mem06 + 4 ; Defines 1 word containing 4 +
; the address of the label mem06
AREA MyData, DATA, READWRITE
DCB 255 ; Now misaligned ...
data3 DCDU 1,5,20 ; Defines 3 words containing
; 1, 5 and 20, not word aligned