| 摘要 |
PURPOSE:To detect a write error in data whose check sum can not be detected by shifting the data contents before the data contents are added. CONSTITUTION:Data in a ROM is denoted as D and a data address value is denoted as A; and a modulo N check function modulo M() is used for the calculation of a bit shift function shift () and a modulo M. Then a weight function corresponding to the write data value is defined for the data contents written in the ROM. Namely, the modulo M is calculated from the data address in a step 1 and the shift value of the data D is determined with N=modulo M(A). In a step 2, the data are shifted on the basis of the shift value N; shift N (D). In a step 3, the shift data are added and a ROM write check sum CS is found from CS=SIGMA (shift N(D)). |
