Answer:
Number of one address instruction
• There are 250 2–address instructions.
• If we have 32–bit instructions allowed, then there are 256 2–address instructions only allowed (two addresses will take 24–bits, leaving 8–bits for the opcode).
• Observing the 8–bit opcode, assume the bit pattern 00000000 (0) to the bit pattern 11111001 (249) are utilized for the 250 2–address instructions.
• Then there are only 6–bit patterns left out for 1–one address instructions.
• Though, each one of these could use the remaining 12–bits attained from possessing only one operand, thus we have 6 * 212 1–address instructions.