| 摘要 |
PROBLEM TO BE SOLVED: To detect overflow and to perform a multiplication accumulation instruction. SOLUTION: The dedicated and general register banks of an N-bit data processing register, a selector, a multiplier and an accumulator are provided or used. The selector is connected to the dedicated and general register banks and selects either of the register banks and the selected register bank outputs N-bit results. The N-bit results and N-bit data held by the general register bank form a 2N-bit additional operand. The multiplier performs a multiplication operation about the 1st and 2nd operands and outputs 2N-bit results. The accumulator is connected to the multiplier, selector and general register bank, performs an accumulation operation about the 2N-bit results and the 2N-bit additional operand and outputs 2N-bit accumulation results. |
