NEC Network Controller uPD98502 - Manual (Page 164)

CHAPTER 2 V R 4120A
164 Preliminary User’s Manual S15543EJ1V0UM
Figure 2-64. Soft Reset and NMI Exception Handling
BD bit ←1
ErrorEPC ←PC−4
Set Status register
BEV bit ←1
TS bit ←0
SR bit ←1
ERL bit ←1
BD bit ←0
ErrorEPC ←PC
(Hardware)
Soft Reset or
NMI exception
Yes
ERL=1?
No
No Yes
Instruction
in branch delay
slot?
PC ←FFFF FFFF BFC0 0000H
(Software)
Servicing by
Cold Reset
exception routine Servicing by
Soft Reset
exception routine
Servicing by NMI
exception routine
The processor provides no means of
distinguishing between an NMI
exception and Soft Reset exception,
so that this must be determined at the
system level.
ERET
Yes
NMI?
No
= 0
SR bit
= 1
Instruction
in delay slot?
BD bit ←1
ErrorEPC ←PC−4
ErrorEPC ←EIM
BD bit ←0
ErrorEPC ←PC
ErrorEPC ←EIM
No Yes
Yes
M16=1?
(config20)
No
•