| 摘要 |
PURPOSE:To attain the detection of a trouble only through a modulo value predicting system by producing a constant and the mask value from the shift count in response to the shift mode and multiplying the modulo value of the AND between the mask value and an operand to be shifted by the constant to predict the modulo value for the shift operation. CONSTITUTION:An operand X is supplied to a shifter 10 and undergoes such shift operations as the right-left shifts, right-left rotations and right-left arithmetic shifts by the number of bits shown by the shift count C in accordance with the shift mode M. Thus the result Z is outputted. Both the shift count C and the mode M are supplied to a mask generating means 20 and the mask value G and a constant K are obtained. A single bit at the left end of the operand X is extended to the left and undergoes the AND with the mask value G through an AND means 30 to be turned into X and G. These AND values X and G are turned into the modulo (m) value (x) by a surplus means 40 and the product is produced by a multiplication means 50 between the constant K and the modulo (m). Then the predicted result (z) is outputted. |
