double, double, double

Multiplying by a power of two never needs a multiply: shifting left by one bit doubles a value, and doing it three times multiplies by eight.

Compute 8 * (a + b) using shifts instead of mulRd = Rn * Rm. Low bits only.. The starter adds up nothing yet; put the sum in the total register and scale it with lslLogical shift left (Rd = Rn << amount)..

what is checked

• the scaled sum is printed on its own line
• the program exits cleanly
• the scaling is done with a left shift, and mulRd = Rn * Rm. Low bits only. stays out of the program