Arm VERSION 1.2 Manual de usuario descargar pdf (Pagina 301)

100

101

Directives Reference

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

1 2 ... 296 297 298 299 300 301 302 303 304 305 306 ... 359 360

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