| Binary Code | Mode | Name | Symbolic | Function
| 000 | 0 | Register
| Rn
| Register contains operand.
| 010 | 2
|
Autoincrement
| (Rn)+
| Register is used as a pointer to sequential
data, then incremented by one for byte and two for word
instruction. R6-R7 are always incremented by two.
| 100 | 4
|
Autodecrement
| -(Rn)
| Register is decremented and then used as a
pointer to sequential data. R0-R5 are decremented by one for
byte and by two for word instructions. R6-R7 are always
decremented by two.
| 110 | 6
|
Index
| X(Rn)
| Value X is added to Rn to produce address of
operand. Neither X nor Rn is modified. X, the index calue is
always found in the next memory location and increments the PC.
| |
| Binary Code | Mode | Name | Symbolic | Function
| 001 | 1
|
Register | Deferred @Rn or (Rn)
| Register contains the address of the operand.
| 011 | 3
|
Autoincrement | Deferred @(Rn)+
| Register is first used as a pointer to a word
containing the address of the operand, then incremented
(always by two, even for byte instructions).
| 101 | 5
|
Autodecrement | Deferred @-(Rn)
| Register is decremented (always by two, even
for byte instructions) and the used as a pointer to a word
containing the address of the operand.
| 111 | 7
|
Index | Deferred @X(Rn)
| Value X (the index is always found in the next
memory location and increments the PC by two) and Rn are
added and the sum is used as a pointer to a word containing
the address of the operand. Neither X nor Rn is modified.
| |
When used with the PC, four of these modes are renamed, as you can see in the table below.
| Binary Code | Mode | Name | Symbolic | Function
| 010 | 2
| Immediate
| #n
| Operand is contained in the instruction.
| 011 | 3
| Absolute
| @#A
| Absolute address in contained in the instruction.
| 110 | 6
| Relative
| A
| Address of A, relative to the instruction, is
contained in the instruction.
| 111 | 7
|
Relative | Deferred @A
| Address of A, relative to the instruction, is
contained in the instruction. Address of the oeprand is
contained in A.
| |