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4 system control coprocessor – NEC Network Controller uPD98502 User Manual

Page 117

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CHAPTER 2 V

R

4120A

Preliminary User’s Manual S15543EJ1V0UM

117

2.4.4 System control coprocessor

The System Control Coprocessor (CP0) is implemented as an integral part of the CPU, and supports memory

management, address translation, exception processing, and other privileged operations. The CP0 contains the

registers and a 32-entry TLB shown in Figure 2-32. The sections that follow describe how the processor uses each of

the memory management-related registers.

Remark

Each CP0 register has a unique number that identifies it; this number is referred to as the register
number.

Figure 2-32. CP0 Registers and TLB

31

0

Remark

TLB

(Safe entries)

(See Random register for

TLB Wired boundary.)

127/255

EntryHi

10*

EntryLo0

2*

Index

0*

Context

4*

BadVAddr

8*

Compare

11*

Count

9*

Random

1*

EntryLo1

3*

PageMask

5*

Status

12*

Cause

13*

WatchLo

18*

EPC

14*

Wired

6*

PRId

15*

WatchHi

19*

XContext

20*

ErrorEPC

30*

Cache Error

27*

Parity Error

26*

LLAddr

17*

TagLo

28*

TagHi

29*

Config

16*

*: Register number

Used for memory management system

Used for exception processing