ADDRESSING
MOTOROLA
ADDRESS GENERATION UNIT 4 - 15
The contents of the address modifier register, Mn, defines the type of arithmetic to be per-
formed for addressing mode calculations. For modulo arithmetic, the contents of Mn also
specifies the modulus, or the size of the memory buffer whose addresses will be refer-
enced. See Table 4-2 for a summary of the address modifiers implemented on the
+
621009BA4C22
15 0
15 0
15 0
EXAMPLE: MOVE Y1,X: (R6+N6)
BEFORE EXECUTION AFTER EXECUTION
Y1 Y0
47 24 23 0
23 0 23 0
X MEMORY
23 0
XXXXXX
$6000
X MEMORY
23 0
$6000
$6000
$FFFF
R6
N6
M6
15 0
15 0
15 0
$6000
$FFFF
R6
N6
M6
Assembler Syntax: (Rn+Nn)
Memory Spaces: P:, X:, Y:, L:
Additional Instruction Execution Time (Clocks): 2
Additional Effective Address Words: 0
XXXXXX
$6004 $6004
XXXXXX
6210 0 9B A4 C2 2
Y1 Y0
47 24 23 0
23 0 23 0
$0004 $0004
$621009
Figure 4-9 Address Register Indirect — Indexed by Offset Nn