Sun Microelectronics
22
UltraSPARC User’s Manual
Figure 4-1
Virtual-to-physical Address Translation for all Page Sizes
UltraSPARC implements a 44-bit virtual address space in two equal halves at the
extreme lower and upper portions of the full 64-bit virtual address space. Virtual
addresses between 0000 0800 0000 0000
16
and FFFF F7FF FFFF FFFF
16
, inclusive,
are termed “out of range” for UltraSPARC and are illegal. (In other words, virtual
address bits VA<63:43> must be either all zeros or all ones.) Figure 4-2 on page 23
illustrates the UltraSPARC virtual address space.
0
0
12
12
13
13
63
40
8K-byte Virtual Page Number
8K-byte Physical Page Number
Page Offset
Page Offset
0
0
15
15
16
16
63
40
64K-byte Virtual Page Number
64K-byte Physical Page Number
Page Offset
Page Offset
0
0
18
18
19
19
63
40
512K-byte Virtual Page Number
512K-byte PPN
Page Offset
Page Offset
VA
PA
PA
PA
VA
VA
8 Kb
64 Kb
512 Kb
0
0
21
21
22
22
63
40
4M-byte Virtual Page Number
4M-byte PPN
Page Offset
Page Offset
PA
VA
4 Mb
MMU
MMU
MMU
MMU
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