Bit-Reversed Addressing
6-27
Addressing Modes
Example 6–26. Bit-Reversed Addressing
*AR2++(IR0)B ;
AR2 =
0110 0000 (0th value)
*AR2++(IR0)B ;
AR2 =
0110 1000 (1st value)
*AR2++(IR0)B ;
AR2 =
0110 0100 (2nd value)
*AR2++(IR0)B ;
AR2 =
0110 1100 (3rd value)
*AR2++(IR0)B ;
AR2 =
0110 0010 (4th value)
*AR2++(IR0)B ;
AR2 =
0110 1010 (5th value)
*AR2++(IR0)B ;
AR2 =
0110 0110 (6th value)
*AR2
;
AR2 =
0110 1110 (7th value)
Table 6–3 shows the relationship of the index steps and the four LSBs of AR2.
You can find the four LSBs by reversing the bit pattern of the steps.
Table 6–3. Index Steps and Bit-Reversed Addressing
Step
Bit Pattern
Bit-Reversed
Pattern
Bit-Reversed
Step
0
0000
0000
0
1
0001
1000
8
2
0010
0100
4
3
0011
1100
12
4
0100
0010
2
5
0101
1010
10
6
0110
0110
6
7
0111
1110
14
8
1000
0001
1
9
1001
1001
9
10
1010
0101
5
11
1011
1101
13
12
1100
0011
3
13
1101
1011
11
14
1110
0111
7
15
1111
1111
15