Question: 1. Why does the 68000 have a supervisor mode (in contrast to many 8-bit microprocessors)? What instructions are privileged, and how do they differ from nonpfivileged instructions?
2. Is the RTE instruction privileged?
3. The 68000 has an instruction, ILLEGAL (with the bit pattern 0100101011111100). When encountered by the 68000, the CPU carries out the operation,
[SSP] ← [SSP] - 4
[M([SSP])] ← [PC]
[SSP] ← [SSP] - 2
[M([SSP])] ← [SR]
[PC] ← [M(16)]
Explain the action of the above sequence of RTL (register transfer language) operations in plain English. Why do you think that such an instruction was implemented by the designers of the 68000?