Define Constant Directive (Dc.w) - Motorola M68CPU32BUG User Manual

When specifying operands, the user may skip or omit entries with the following addressing
modes.
Address register indirect with index, base displacement.
Program counter indirect with index, base displacement.
For the above modes, the rules for omission/skipping are as follows:
The user may terminate the operand by specifying '')''.
EXAMPLE
CLR
CLR
CLR
The user may skip a field by stepping past it with a comma.
EXAMPLE
CLR
CLR
but
CLR
CLR
If the user does not specify the base register, the default is ''ZA0''. When Z precedes
the register number, it indicates that register is suppressed.
If the user does not specify the index register, the default is ''ZD0.W*1''.
Any unspecified displacements are defaulted to ''0''.
4.2.3

Define Constant Directive (DC.W)

The format for the DC.W directive is:
DC.W <operand >
This directive defines a constant in memory. The DC.W directive has only one operand (16-bit
value) which can contain the actual value (decimal, hexadecimal, or ASCII). Alternatively, the
operand can be an expression which is assigned a numeric value by the assembler. The constant
is aligned on a word boundary if word (.W) size is specified. An ASCII string is recognized when
characters are enclosed inside single quotes marks (' . . . '). Each character (7 bits) is assigned to a
byte of memory with the eighth bit (MSB) always equal to zero. If only one byte is entered, the
byte is right justified. A maximum of two ASCII characters may be entered for each DC.W
directive.
M68CPU32BUG/D
( ) or
(,,) is equivalent to
(0.N,ZA0,ZD0.W*1)
(D7) is equivalent to
($D7,ZA0,ZD0.W*1)
(,,D7) is equivalent to
(0.N,ZA0,D7.W*1)
4-9
ASSEMBLER/DISASSEMBLER