In one embodiment, a rotator, a mask generator, and circuitry configured to mask the rotated operand output by the rotator with the output mask generated by the mask generator perform a shift operation. The rotator is configured to rotate the input operand by the shift count. The mask generator is configured to generate an output mask by decoding a most significant bit (MSB) field of the shift count to generate a first mask, decoding a least significant bit (LSB) field of the shift count to generate a second mask, logically ANDing the bits of the second mask with the corresponding bit of the first mask and logically ORing the result with an adjacent bit of the first mask that is selected responsive to the shift direction.