r4f2456 Renesas Electronics Corporation., r4f2456 Datasheet - Page 132

• Manufacturer Part Number: r4f2456
• Description: 16-bit Single-chip Microcomputer H8s Family / H8s/2400 Series
• Manufacturer: Renesas Electronics Corporation.

Section 4 Exception Handling
4.7
Illegal instruction exception handling starts when the CPU executing an illegal instruction code is
detected. Illegal instruction exception handling can be executed at all times in the program
execution state.
The illegal instruction exception handling is as follows:
1. The values in the PC, CCR, and EXR are saved in the stack.
2. The interrupt mask bit is updated and the T bit is cleared to 0.
3. An exception handling vector table address corresponding to the exception is generated, the
Table 4.5 shows the status of CCR and EXR after execution of illegal instruction exception
handling.
Table 4.5
Legend:
1:
0:
—: Retains value prior to execution
Illegal instruction codes will not be searched for in the fields that do not affect instruction
definitions, such as the EA extension or register fields. Instruction codes for an instruction formed
with several words are detected independently, and combined instruction codes are not detected.
Undefined instruction codes must not be executed. The general register contents after execution of
an undefined instruction code or illegal instruction exception handling cannot be guaranteed. The
stack pointer during illegal instruction exception handling and the PC value that will be saved are
also not guaranteed.
Rev. 1.00 Sep. 19, 2008 Page 102 of 1342
REJ09B0467-0100
Interrupt Control Mode
0
2
start address of the exception service routine is loaded from the vector table to the PC, and
program execution starts from that address.
Set to 1
Cleared to 0
Illegal Instruction Exception Handling
Status of CCR and EXR after Illegal Instruction Exception Handling
I
1
1
CCR
UI


T

0
EXR
I2 to I0

