Exception Handling By Illegal Instruction; Table 4.9 Status Of Ccr And Exr After Illegal Instruction Exception Handling - Renesas H8SX/1520 Series Hardware Manual

32-bit cisc microcomputer

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Section 4 Exception Handling

Exception Handling by Illegal Instruction

There are two illegal instructions: general illegal instruction and slot illegal instruction.

The exception handling by the general illegal instruction starts when an undefined code is

The exception handling by the slot illegal instruction starts when the following instruction which

is placed in a delay slot (immediately after a delayed branch instruction) is executed: an

instruction which consists of two words or more or which changes the contents of PC.

The general illegal and slot illegal instructions are always executable in the program execution

The exception handling for the general illegal and a slot illegal instructions is as follows:

1. The contents of 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 occurred exception is

generated, the start address of the exception service routine is loaded from the vector table to

PC, and program execution starts from that address.

Table 4.9 shows the state of CCR and EXR after execution of illegal instruction exception

Status of CCR and EXR after Illegal Instruction Exception Handling

Interrupt Control Mode

Cleared to 0

Retains the previous value.

Rev. 3.00 Mar. 14, 2006 Page 84 of 804

REJ09B0104-0300

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