Generation Of Actual Addresses Indirect, Virtual Addressing - Xerox 560 Reference Manual

Instruction in memory:
Instruction in instruction registers:
The 8 high-order bits of the reference address are
replaced with ll-bit page address Z from memory map:
Actual address of memory location that contains
the direct address:
17-bit direct address in memory:
Indi rect addressing replaces reference address
with direct address:
Halfword operation indexing alignment:
Effective virtual address:
The 8 high-order bits of the effective address are
replaced with ll-bit page address N from memory map:
Final memory address, which is the actual address of
halfword location containing the effective halfword:
\.
,-------~·------~'r~------~~~----~
22-bit actual address
III
III
I II I
1119-bit virtual1halfword address
I
l, I... l, I ... I ... I ... I, I, , , , , " , , ,
£"
I" " " " "
"r\."
I I I I I I I I I
I
VI
15116 17 18 19120 2122 2312425 26 27128 29 30 31
1
3233
,
...
o
1 2 3 4 5
...
I
1
I
Figure 7. Generation of Actual Addresses Indirect, Virtual Addressing
22 Main Memory