1. Addressing Modes Immediate #<data> or Imm
data is part of the instruction
Register Direct Dn or An
data is in a register
the register number is part of the instruction
Memory Direct (xxx).W or (xxx).L
data is in a memory location
the address of the memory location is part of the instruction
Address Register Indirect (An)
the address of the data is in the address register

2. Address Register Indirect … variations
Autoincrement (An)+
address register indirect with postincrement
operand is written as (An)+
the address of the data is in the address register
registers
memory
address
data
instruction

3. Address Register Indirect … variations
Autodecrement -(An)
address register indirect with predecrement
operand is written as -(An)
the address of the data is the contents of the address register minus the decrement
registers
memory
instruction
address
data

4. Postincrement and Predecrement
going backward MOVE.B list_l,D0 loop2 NEG.W -(A0) SUBQ.B #1,D0 BNE loop2 …
list_l DC.B list DC.W ,2,4,0 count DS.B 1
going forward
LEA list,A0 MOVE.B list_l,D0 loop1 NEG.W (A0)+ SUBQ.B #1,D0 BNE loop1
… * where is A0 positioned?

5. e.g. Determine the number of negative elements in a series of signed 16 bit numbers. Length of array is provided.
input:
output:
algorithm:

6. Reading: Expectations:
M /16-/32-Bit Microprocessors User’s Manual [pdf, 184p; Motorola] -- Table 2-1. Data Addressing Modes, from section 2.2, the <ea> information is correct
MOTOROLA M68000 FAMILY Programmer’s Reference Manual [pdf, 646p; Motorola] -- Section 2 Addressing Capabilities: subsections covers indirect addressing; note that the diagram and the <ea> information in is wrong as it shows address register indirect with preincrement not postincrement
Expectations:
you can use LEA and MOVEA to correctly initialize an address register to traverse the list/array in either direction
you can use indirect addressing variations correctly and to your advantage