According to the M68000UM, the two unimplemented instruction exceptions
both cost 34 cycles, not 4.
Actually, that's a bit of a lie. Table 8-14. Exception Processing
Execution Times does not even mention unimplemented instruction
exceptions, but section 6.3.6 Illegal and Unimplemented Instructions
basically says that unimplemented instructions are just a special case
of illegal instructions in that they have separate exception vectors.
According to the M68000UM, the two unimplemented instruction exceptions both cost 34 cycles, not 4.
Actually, that's a bit of a lie. Table 8-14. Exception Processing Execution Times does not even mention unimplemented instruction exceptions, but section 6.3.6 Illegal and Unimplemented Instructions basically says that unimplemented instructions are just a special case of illegal instructions in that they have separate exception vectors.