The RST 7 instruction in the 8085 microprocessor is equivalent to:
2015
The RST 7 instruction in the 8085 microprocessor is equivalent to:
Answer: C. CALL 0038 H — ConceptIn the 8085, a restart instruction RST n transfers control to the fixed vector address 8 × n in decimal. The one-byte instruction saves the return…
- A.
CALL 0010 H
- B.
CALL 0034 H
- C.
CALL 0038 H
- D.
CALL 003C H
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Correct answer: C
Concept
In the 8085, a restart instruction RST n transfers control to the fixed vector address 8 × n in decimal. The one-byte instruction saves the return address and loads the program counter with that vector, so its control transfer is equivalent to a CALL to the same address.
A valid RST vector is therefore a multiple of 8, and dividing the vector address by 8 recovers the restart number n.
Application
Set n = 7 in the vector formula: address = 8 × 7 = 56 decimal.
Convert 56 to hexadecimal: 56 = 3 × 16 + 8, so the address is
0x38.Write the 16-bit call target with leading zeros:
0038H. The equivalent instruction isCALL 0038H.
Cross-check
Dividing 0x38 (56 decimal) by 8 gives quotient 7 with remainder 0, which recovers RST 7 and confirms the vector boundary.
Result
Therefore, RST 7 is equivalent to CALL 0038H.