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Allowed operators are:
Addition
Subtraction
Multiply
Divide
Shift left
Shift right
Bitwise or
Bitwise and
The order of evaluation is strictly left to right with no precedence granted to some operators over
others. The only exception is when the user forces the order of precedence via the use of
parentheses.
Possible points of confusion:
Differentiate numbers and registers to avoid confusion. For example:
CLR
CLR
CLR
CLR
CLR
With the use of asterisk (*) to represent both multiply and program counter,
how does the assembler know when to use which definition?
For parsing algebraic expressions, the order of parsing is
with a possible left or right parenthesis.
Given the above order, the assembler can distinguish by placement which
definition to use. For example:
*&&16
M68CPU32BUG/D
+
-
*
/
<<
>>
!
&
D0
means CLR.W register D0. On the other hand,
$D0
0D0
+D0
D0+0 all mean CLR.W memory location $D0.
<OPERAND> <OPERATOR> <OPERAND> <OPERATOR>
***
Means
*+*
Means
2**
Means
Means
PC
*
PC
+
2
*
PC
AND
4-8
ASSEMBLER/DISASSEMBLER
PC
PC
PC
&16
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