NEC Network Controller uPD98502 - Manual (Page 163)

CHAPTER 2 V R 4120A
Preliminary User’s Manual S15543EJ1V0UM 163
Figure 2-63. Cold Reset Exception Handling
(Hardware)
PC ←FFFF FFFF BFC0 0000H
(Software)
• 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.
Servicing by
Cold Reset
exception routine Servicing by
Soft Reset
exception routine
Servicing by NMI
exception routine
ERET
BD bit ←1
ErrorEPC ←PC−4
Random register ←31
Wired register ←0
Update Config register bit
31:28||Undef(27:23)||22:6||Undef(5:0)
Set Status register
BEV bit ←1
TS bit ←0
SR bit ←0
ERL bit ←1
BD bit ←0
ErrorEPC ←PC
Cold Reset
Exception
Yes
ERL=1?
No
No Yes
Instruction
in branch delay
slot?
Yes
NMI?
No
= 0
SR bit
= 1
Yes
M16=1?
(config20)
No Instruction
in delay slot?
BD bit ←0
ErrorEPC ←PC
ErrorEPC ←EIM
BD bit ←1
ErrorEPC ←PC−4
ErrorEPC ←EIM
No Yes