4.9.14 Dw Directive

The DW directive is used to initialize 16-bit words of program memory.

The directive takes a comma-separated list of arguments. Each argument can be a numeric value (e.g., 55), a character constant (e.g. 'T'), or a string (e.g. "level" or 'level'). Each argument or each character of a string argument is written as two bytes into consecutive program memory locations within the current psect.

In the following code:

PSECT myWords,class=CODE,delta=2
alabel:
  DW  'X',1,2,398,5472

the DW directive will initialize each word of program memory with the supplied value, specifically (in hexadecimal):

0058 0001 0002 018E 1560

Strings consist of a sequence of characters enclosed within either single or double quotes. There is no termination character added by the assembler. If you need a nul-terminated string, then specify the termination character as a separate argument to the DW directive, for example:

PSECT myConst,class=CODE,delta=1
words:
        DW "a terminated string",0

will define:

0061 0020 0074 0065 0072 006D 0069 006E 0061 0074 0065 0064 0020 0073 0074 0072 0069 006E 0067 0000

The DW directive cannot be used to created objects in data memory. For that, use the DS directive (see 4.9.13 Ds Directive).