Computer Hardware User's Guide

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