The microoperation which divides a signed binary number by 2 is:

Answer: Arithmetic shift right

Why: An arithmetic right shift moves all bits one position to the right and copies the original sign bit into the new leftmost position. This preserves the sign of two's-complement signed numbers and therefore implements integer division by 2 (with truncation toward negative infinity for odd negative values).

• Example (positive): 8 in 8-bit binary is 00001000. Arithmetic right shift → 00000100 which is 4.

• Example (negative): -3 in 8-bit two's complement is 11111101. Arithmetic right shift → 11111110 which is -2 (floor of -1.5).

Contrast with other shifts:

• Logical shift right: inserts zeros into the leftmost bits and is appropriate for unsigned numbers; it does not preserve the sign bit for signed values.

• Circular shift (rotate): moves bits end-to-end (the bit shifted out at one end reappears at the other); this does not correspond to dividing by 2.

• Arithmetic shift left: shifts bits left and inserts a zero in the least significant bit, effectively multiplying by 2 rather than dividing.

Summary: Use arithmetic shift right to divide signed binary numbers by 2 because it preserves the sign bit and yields the expected integer result.