DC - Define Constant

Syntax

  [<label>:]  DC [.<size>] <expression> [, 
  <expression>]...

where <size> = B (default), W, or L.

Synonym

  DCW (= 2 byte DCs),  DCL (= 4 byte DCs),
  
  FCB (= DC.B), FDB    (= 2 byte DCs),
  
  FQB (= 4 byte DCs)

Description

The DC directive defines constants in memory. It can have one or more <expression> operands, which are separated by commas. The <expression> can contain an actual value (binary, octal, decimal, hexadecimal, or ASCII). Alternatively, the <expression> can be a symbol or expression that can be evaluated by the Assembler as an absolute or simple relocatable expression. One memory block is allocated and initialized for each expression.

The following rules apply to size specifications for DC directives:

DC.B: One byte is allocated for numeric expressions. One byte is allocated per ASCII character for strings.
Listing: Example for DC.B
```
000000 4142 4344   Label: DC.B "ABCDE"
000004 45

000005 0A0A 010A          DC.B %1010, @12, 1,$A
```

DC.W: Two bytes are allocated for numeric expressions. ASCII strings are right aligned on a two-byte boundary.

Listing: Example for DC.W


000000 0041 4243   Label: DC.W "ABCDE"
000004 4445

000006 000A 000A          DC.W %1010, @12, 1, $A

00000A 0001 000A

00000E xxxx               DC.W Label

DC.L: Four bytes are allocated for numeric expressions. ASCII strings are right aligned on a four byte boundary.

Listing: Example for DC.L


000000 0000 0041   Label: DC.L "ABCDE"
000004 4243 4445

000008 0000 000A          DC.L %1010, @12, 1, $A

00000C 0000 000A

000010 0000 0001

000014 0000 000A

000018 xxxx xxxx          DC.L Label

If the value in an operand expression exceeds the size of the operand, the assembler truncates the value and generates a warning message.

See also

Assembler directives: