90
Chapter 3
CPU Functions
User’s Manual U16580EE3V1UD00
(2)
NMI status saving registers (FEPC, FEPSW)
There are two NMI status saving registers, FEPC and FEPSW.
Upon occurrence of a non-maskable interrupt (NMI), the content of the program counter (PC) is
saved to FEPC and the content of the program status word (PSW) is saved to FEPSW.
The address of the next instruction following the instruction executed when a non-maskable
interrupt occurs is saved to FEPC, except for the DIVH instruction.
Bits 31 to 26 of FEPC and bits 31 to 8 of FEPSW are reserved (fixed to 0) for future function
expansion.
Figure 3-4:
NMI Status Saving Registers (FEPC, FEPSW)
The values of FEPC and FEPSW are restored to PC and PSW during execution of a RETI
instruction.
(3)
Exception cause register (ECR)
Upon occurrence of an interrupt or an exception, the Exception Cause Register (ECR) holds the
source of the interrupt or the exception. The value held by ECR is an exception code, coded for
each interrupt source. This register is a read-only register, and thus data cannot be written to it
using the LDSR instruction.
Figure 3-5:
Interrupt Source Register (ECR)
The list of exception codes is tabulated in
Table 7-1, “Interrupt/Exception Source List,” on
.
31
26 25
0
After reset
0xxxxxxxH
(x: Undefined)
FEPC
0 0 0 0 0 0
(PC contents)
31
8 7
0
After reset
000000xxH
(x: Undefined)
FEPSW
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
(PSW contents)
31
16 15
0
After reset
00000000H
ECR
FECC
EICC
Bit position
Bit name
Description
31 to 16
FECC
Non-maskable interrupt (NMI) exception code
15 to 0
EICC
Exception, maskable interrupt exception code
Summary of Contents for MuPD70F3187
Page 6: ...6 Preface User s Manual U16580EE3V1UD00 ...
Page 16: ...16 User s Manual U16580EE3V1UD00 ...
Page 28: ...28 User s Manual U16580EE3V1UD00 ...
Page 32: ...32 User s Manual U16580EE3V1UD00 ...
Page 84: ...84 Chapter 2 Pin Functions User s Manual U16580EE3V1UD00 MEMO ...
Page 144: ...144 Chapter 3 CPU Functions User s Manual U16580EE3V1UD00 MEMO ...
Page 312: ...312 Chapter 9 16 Bit Timer Event Counter P User s Manual U16580EE3V1UD00 MEMO ...
Page 534: ...534 Chapter 11 16 bit Timer Event Counter T User s Manual U16580EE3V1UD00 ...
Page 969: ...969 Chapter 20 Port Functions User s Manual U16580EE3V1UD00 MEMO ...
Page 970: ...970 Chapter 20 Port Functions User s Manual U16580EE3V1UD00 ...
Page 976: ...976 Chapter 22 Internal RAM Parity Check Function User s Manual U16580EE3V1UD00 MEMO ...
Page 984: ...984 Chapter 23 On Chip Debug Function OCD User s Manual U16580EE3V1UD00 MEMO ...
Page 1006: ...1006 Chapter 24 Flash Memory User s Manual U16580EE3V1UD00 MEMO ...
Page 1036: ...1036 Chapter 27 Recommended Soldering Conditions User s Manual U16580EE3V1UD00 MEMO ...
Page 1046: ...1046 Appendix A Index User s Manual U16580EE3V1UD00 MEMO ...
Page 1052: ...1052 User s Manual U16580EE3V1UD00 ...
Page 1053: ......