| 摘要 |
PURPOSE:To share and protect a memory by adding the offset values of different numbers to the memory addresses outputted from a CPU and producing the access address of a shared memory from the memory address and the offset value. CONSTITUTION:An offset setting part 4 sets the offset values at every CPU in response to the different numbers. An offset adding circuit 5 adds the 2-bit offset value 8 of the part 4 to an output memory address 9 of a CPU 6 and sends it to a common bus 3 in the form of an access address 7. Therefore the area of a common memory 1 is divided into four pieces in response to four processors 2a-2d. Thus the processors 2a-2d have the equivalent effects as those of an exclusive local memory starting at an address 0. Then these processors can share the memory 1 and the access area of the CPU is specified. Thus the memory 1 is easily protected. |
