SH7040 Datasheet, PDF (134/923 Pages) Renesas Technology Corp – Renesas 32-Bit Single-Chip RISC Microprocessor SuperH RISC engine Family/SH7040 Series(CPU Core SH-2)

5.5.3 General Illegal Instructions
When undefined code placed anywhere other than immediately after a delayed branch instruction
(i.e., in a delay slot) is decoded, general illegal instruction exception processing starts up. The
CPU handles general illegal instructions the same as illegal slot instructions. Unlike processing of
illegal slot instructions, however, the program counter value stored is the start address of the
undefined code.
5.6 When Exception Sources Are Not Accepted
When an address error or interrupt is generated after a delayed branch instruction or interrupt-
disabled instruction, it is sometimes not accepted immediately but stored instead, as shown in
table 5.10. When this happens, it will be accepted when an instruction that can accept the
exception is decoded.
Table 5.10 Generation of Exception Sources Immediately after a Delayed Branch
Instruction or Interrupt-Disabled Instruction
Exception Source
Point of Occurrence
Address Error
Interrupt
Immediately after a delayed branch instruction^*1
Not accepted
Not accepted
Immediately after an interrupt-disabled instruction^*2
Accepted
Not accepted
Notes: *1 Delayed branch instructions: JMP, JSR, BRA, BSR, RTS, RTE, BF/S, BT/S, BSRF,
BRAF
*2 Interrupt-disabled instructions: LDC, LDC.L, STC, STC.L, LDS, LDS.L, STS, STS.L
5.6.1 Immediately after a Delayed Branch Instruction
When an instruction placed immediately after a delayed branch instruction (delay slot) is decoded,
neither address errors nor interrupts are accepted. The delayed branch instruction and the
instruction located immediately after it (delay slot) are always executed consecutively, so no
exception processing occurs during this period.
5.6.2 Immediately after an Interrupt-Disabled Instruction
When an instruction immediately following an interrupt-disabled instruction is decoded, interrupts
are not accepted. Address errors are accepted.
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