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2.4.2.3 64-bit mode address translation
Figure 2-27 shows the virtual-to-physical-address translation of a 64-bit mode address. This figure illustrates the
two possible page size; a 1-Kbyte page (10 bits) and a 256-Kbyte page (18 bits).
Shown at the top of Figure 2-27 is the virtual address space in which the page size is 1 Kbyte and the offset
is 10 bits. The 30 bits excluding the ASID field represents the virtual page number (VPN), enabling selecting
a page table of 1 G entry.
Shown at the bottom of Figure 2-27 is the virtual address space in which the page size is 256 Kbytes and the
offset is 18 bits. The 22 bits excluding the ASID field represents the VPN, enabling selecting a page table of
4 M entries.
71
ASID
8
Bits 62 and 63 of the virtual
address select the user,
supervisor, or kernel
address space.
71
ASID
8
CHAPTER 2 V
Figure 2-27. 64-bit Mode Virtual Address Translation
Virtual address for 1 G (2
64
63
62
61
40
39
0 or -1
24
30
30 bits = 1 G pages
TLB
31
PFN
Virtual-to-physical address
translation with the TLB
TLB
62
64
63
61
40
39
0 or -1
VPN
24
22
22 bits = 4 M pages
22
Virtual address for 4 M (2
) 256-Kbyte pages
Preliminary User's Manual S15543EJ1V0UM
4120A
R
30
) 1-Kbyte pages
10
9
VPN
Virtual-to-physical address
translation with the TLB
32-bit physical address
18
17
Offset
18
0
Offset
10
The offset is passed to
physical address without
being changed.
0
Offset
The offset is passed to
physical address without
being changed.
0
105
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