Based on the above picture: a) For each of the following instructions, for each

Question

Based on the above picture:

a) For each of the following instructions, for each starting at fetch1, list the names of microcode instructions used to execute the instruction. Then give the corresponding number of cycles and indicate whether the instruction returns to fetch1 or to fetch2.

inca

adda $23

sta [$C6]

suba [X+3]

b) Discuss why the pshx instruction appears to execute in fewer cycles than the popx instruction. Trace each instruction to determine how many cycles each takes. What special feature do some implied instructions have?

5 Data Data Bus ax Address Bus Address di Data di Data ND DX IR DX ALU F Y ALU F Y 2 Data Data Bus ax Address Bus Address Data Data DX DX ALU F Y F Y Data Bus 2 2 Data Bus 3 ax Address Bus ax Address Bus di Data Data DX ALU F Y F Y

Explanation / Answer

Ans:a)For each starting at fetch1,the microcode instructions used to execute the instruction are executed by ALU.The corresponding number of cycles and infdicate whether the instruction returns to fetch1 or to fetch2 is nearly 100.

b)The pshx instruction appears to execute in fewer cycles than the popx instruction because when the DDR bit is set to 1, the pin behaves as an output pin that is driven low.The port corresponding to the pin was previously written to 0 and the associated pullup was enabled.So nearly 4 to 5 cycles are there for instructions.

Related Questions

Navigate

• Browse (All)
• Browse B
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.