32170 Datasheet, PDF (109/881 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 32-BIT CMOS MICROCOMPUTER

4
EIT
4.8 Exception Processing
+0 +1 +2 +3
Address
Return
address
H’00
H’04
H’08
H’0C
AE occurred
+0
Address
Return
address
H’00
H’04
H’08
H’0C
+1 +2 +3
AE occurred
BPC
H’04
BPC
H’06
Figure 4.8.2 Example of a Return Address for Address Exception (AE)
(4) Branching to the EIT vector entry
Control branches to the address H'0000 0030 in the user space. This is the last operation
performed in hardware preprocessing by the M32R/ECU.
(5) Jumping from the EIT vector entry to the user-created handler
The M32R/ECU executes the "BRA" instruction written at address H'0000 0030 of the EIT
vector entry by the user to jump to the start address of the user-created handler. At the
beginning of the EIT handler you created, first save the BPC and PSW registers and the
necessary general-purpose registers to the stack.
(6) Returning from the EIT handler
At the end of the EIT handler, restore the general-purpose registers and the BPC and PSW
registers from the stack and then execute the "RTE" instruction. As you execute the "RTE"
instruction, hardware postprocessing is automatically performed by the M32R/ECU.
4-14
32170/32174 Group User's Manual (Rev. 2.1)