Chapter 4
76 MIPS R4000 Microprocessor User's Manual
32-bit Kernel Mode, Kernel Space 1 (kseg1)
In Kernel mode, when KX = 0 in the Status register and the most-
significant three bits of the 32-bit virtual address are 101
2
, 32-bit kseg1
virtual address space is selected; it is the 2
29
-byte (512-Mbyte) kernel
physical space.
References to kseg1 are not mapped through the TLB; the physical address
selected is defined by subtracting 0xA000 0000 from the virtual address.
Caches are disabled for accesses to these addresses, and physical memory
(or memory-mapped I/O device registers) are accessed directly.
32-bit Kernel Mode, Supervisor Space (ksseg)
In Kernel mode, when KX = 0 in the Status register and the most-
significant three bits of the 32-bit virtual address are 110
2
, the ksseg virtual
address space is selected; it is the current 2
29
-byte (512-Mbyte) supervisor
virtual space. The virtual address is extended with the contents of the 8-
bit ASID field to form a unique virtual address.
32-bit Kernel Mode, Kernel Space 3 (kseg3)
In Kernel mode, when KX = 0 in the Status register and the most-
significant three bits of the 32-bit virtual address are 111
2
, the kseg3 virtual
address space is selected; it is the current 2
29
-byte (512-Mbyte) kernel
virtual space. The virtual address is extended with the contents of the 8-bit
ASID field to form a unique virtual address.
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