| 摘要 |
<p>1474280 Data processing systems XEROX CORP 6 Aug 1974 [6 Aug 1973] 53355/76 Divided out of 1474279 Heading G4A The disclosure is substantially identical to that of the parent Specification. The claims are directed to a method using a micro-programmable memory in a computer to implement a variable field addressing capability comprising the steps of: accessing the variable field instruction from the main memory; storing the instruction in a register in the c.p.u. of the computer; branching to a micro-program subroutine in the control memory, the selected sub-routine corresponding to the function of the instruction; accessing a fixed length data word containing the variable field from the main memory ; storing the data word in a data register in the c.p.u.; right justifying the variable field in the register; operating on the justified variable field according to the function of the instruction; and, if the instruction is a store instruction, shifting the variable field back to its original position; masking the variable field into the data word in the data register; and storing the contents of the data register in its original position in the main memory.</p> |
