Mips Technologies R4000 - Exception Processing Registers

MIPS R4000 Microprocessor User's Manual 71
Memory Management
Table 4-2 32-bit and 64-bit Supervisor Mode Segments
32-bit Supervisor Mode, User Space (suseg)
In Supervisor mode, when SX = 0 in the Status register and the most-
significant bit of the 32-bit virtual address is set to 0, the suseg virtual
address space is selected; it covers the full 2
31
bytes (2 Gbytes) 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 0x0000 0000 and runs through
0x7FFF FFFF.
32-bit Supervisor Mode, Supervisor Space (sseg)
In Supervisor mode, when SX = 0 in the Status register and the three most-
significant bits of the 32-bit virtual address are 110
2
, the sseg virtual
address space is selected; it covers 2
29
-bytes (512 Mbytes) of the current
supervisor 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 0xC000 0000 and runs
through 0xDFFF FFFF.
Address Bit
Values
Status Register
Segment
Name
Address Range
Segment
Size
Bit Values
KSU EXL ERL SX
32-bit
A(31) = 0
01
2
000suseg
0x0000 0000
through
0x7FFF FFFF
2 Gbytes
(2
31
bytes)
32-bit
A(31:29) = 110
2
01
2
000ssseg
0xC000 0000
through
0xDFFF FFFF
512 Mbytes
(2
29
bytes)
64-bit
A(63:62) = 00
2
01
2
001xsuseg
0x0000 0000 0000 0000
through
0x0000 00FF FFFF FFFF
1 Tbyte
(2
40
bytes)
64-bit
A(63:62) = 01
2
01
2
001xsseg
0x4000 0000 0000 0000
through
0x4000 00FF FFFF FFFF
1 Tbyte
(2
40
bytes)
64-bit
A(63:62) = 11
2
01
2
001csseg
0xFFFF FFFF C000 0000
through
0xFFFF FFFF DFFF FFFF
512 Mbytes
(2
29
bytes)