NEC Network Controller uPD98502 - Manual (Page 109)

CHAPTER 2 V R 4120A
Preliminary User’s Manual S15543EJ1V0UM 109
Table 2-28. 32-bit and 64-bit Supervisor Mode Segments
Address Bit Status Register Bit Value Segment Address Range Size
Value KSU EXL ERL SX Name
32-bit
A31 = 0
01 0 0 0 suseg 0000_0000H
to
7FFF_FFFFH
2 Gbytes
(2
31
bytes)
32-bit
A(31:29) =
110
01 0 0 0 sseg C000_0000H
to
DFFF_FFFFH
512
Mbytes
(2
29
bytes)
64-bit
A(63:62) = 00
01 0 0 1 xsuseg 0000_0000_0000_0000H
to
0000_00FF_FFFF_FFFFH
1 Tbyte
(2
40
bytes)
64-bit
A(63:62) = 01
01 0 0 1 xsseg 4000_0000_0000_0000H
to
4000_00FF_FFFF_FFFFH
1 Tbyte
(2
40
bytes)
64-bit
A(63:62) = 11
01 0 0 1 csseg FFFF_FFFF_C000_0000H
to
FFFF_FFFF_DFFF_FFFF
H
512
Mbytes
(2
29
bytes)
(1) suseg (32-bit supervisor mode, user space)
When SX = 0 in the Status register and the most-significant bit of the virtual address space is set to 0, the suseg
virtual address space is selected; it covers 2 Gbytes (2
31
bytes) of the current user address space. The virtual
address is extended with the contents of the 8-bit ASID field to form a unique virtual address. This mapped space
starts at virtual address 0000_0000H and runs through 7FFF_FFFFH.
(2) sseg (32-bit supervisor mode, supervisor space)
When SX = 0 in the Status register and the most-significant three bits of the virtual address space are 110, the
sseg virtual address space is selected; it covers 512 Mbytes (2
29
bytes) of the current supervisor virtual address
space. The virtual address is extended with the contents of the 8-bit ASID field to form a unique virtual address.
This mapped space begins at virtual address C000_0000H and runs through DFFF_FFFFH.
(3) xsuseg (64-bit supervisor mode, user space)
When SX = 1 in the Status register and bits 63 and 62 of the virtual address space are set to 00, the xsuseg virtual
address space is selected; it covers 1 Tbyte (2
40
bytes) of the current user address space. The virtual address is
extended with the contents of the 8-bit ASID field to form a unique virtual address. This mapped space starts at
virtual address 0000_0000_0000_0000H and runs through 0000_00FF_FFFF_FFFFH.
(4) xsseg (64-bit supervisor mode, current supervisor space)
When SX = 1 in the Status register and bits 63 and 62 of the virtual address space are set to 01, the xsseg virtual
address space is selected; it covers 1 Tbyte (2
40
bytes) of the current supervisor virtual address space. The virtual
address is extended with the contents of the 8-bit ASID field to form a unique virtual address. This mapped space
begins at virtual address 4000_0000_0000_0000H and runs through 4000_00FF_FFFF_FFFFH.
(5) csseg (64-bit supervisor mode, separate supervisor space)
When SX = 1 in the Status register and bits 63 and 62 of the virtual address space are set to 11, the csseg virtual
address space is selected; it covers 512 Mbytes (2
29
bytes) of the separate supervisor virtual address space. The
virtual address is extended with the contents of the 8-bit ASID field to form a unique virtual address. This mapped
space begins at virtual address FFFF_FFFFH_C000_0000 and runs through FFFF_FFFF_DFFF_FFFFH.