Datasheet

Section 4 Exception Handling

Rev.7.00 Feb. 14, 2007 page 106 of 1108

REJ09B0089-0700

4.5 Trap Instruction

Trap instruction exception handling starts when a TRAPA instruction is executed. Trap instruction

exception handling can be executed at all times in the program execution state.

The TRAPA instruction fetches a start address from a vector table entry corresponding to a vector

number from 0 to 3, as specified in the instruction code.

Table 4.4 shows the status of CCR and EXR after execution of trap instruction exception handling.

Table 4.4 Status of CCR and EXR after Trap Instruction Exception Handling

CCR EXR

Interrupt Control Mode I UI I2 to I0 T

0 1 — — —

2 1 — — 0

Legend:

1: Set to 1

0: Cleared to 0

—: Retains value prior to execution.

4.6 Stack Status after Exception Handling

Figure 4.4 shows the stack after completion of trap instruction exception handling and interrupt

exception handling.

CCR

(24 bits)

CCR

(24 bits)

Reserved*

EXR

(a) Interrupt control mode 0 (b) Interrupt control mode 2

Note: * Ignored on return.

Figure 4.4 Stack Status after Exception Handling (Advanced Modes)