IDT79R3052 データシートの表示（PDF） - Integrated Device Technology

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IDT79R3052

RISControllers

Integrated Device Technology 

IDT79R3051/79R3052 INTEGRATED RISControllers

0xffffffff

VIRTUAL

Kernel Mapped

(kseg2)

Any

0xc0000000

0xa0000000

0x80000000

Kernel Uncached

(kseg1)

Kernel Cached

(kseg0)

PHYSICAL

COMMERCIAL TEMPERATURE RANGE

Physical

Memory

3548MB

User Mapped

Cacheable

(kuseg)

Any

0x00000000

Memory

512MB

Figure 3. Virtual-to-Physical Mapping of Extended Architecture Versions

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The base versions of the architecture (the IDT79R3051

and IDT79R3052) remove the TLB and institute a fixed

address mapping for the various segments of the virtual

address space. The base processors support distinct kernel

and user mode operation without requiring page management

software, leading to a simpler software model. The memory

mapping used by these devices is illustrated in Figure 4. Note

that the reserved address spaces shown are for compatibility

with future family members; in the current family members,

references to these addresses are translated in the same

fashion as their respective segments, with no traps or excep-

tions taken.

VIRTUAL

When using the base versions of the architecture, the

system designer can implement a distinction between the

user tasks and the kernel tasks, without having to execute

page management software. This distinction can take the

form of physical memory protection, accomplished by ad-

dress decoding, or in other forms. In systems which do not

wish to implement memory protection, and wish to have the

kernel and user tasks operate out of a single unified memory

space, upper address lines can be ignored by the address

decoder, and thus all references will be seen in the lower

gigabyte of the physical address space.

PHYSICAL

0xffffffff

1MB Kernel Rsvd

0xc0000000

0xa0000000

0x80000000

Kernel Cached

(kseg2)

Kernel Uncached

(kseg1)

Kernel Cached

(kseg0)

1MB User Rsvd

Kernel Cacheable

Tasks

1024MB

Kernel/User

Cacheable

Tasks

2048MB

0x00000000

User

Cached

(kuseg)

Inaccessible

Kernel Boot

and I/O

512MB

512MB

Figure 4. Virtual-to-Physical Mapping of Base Architecture Versions

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5.3

3

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