| 摘要 |
PROBLEM TO BE SOLVED: To achieve a high-speed RMW(read modify write) operation for z- buffer for 3DCG(3-dimensional computer graphics). SOLUTION: A semiconductor storage has a memory array 2 that can input and output data independently for read/write, a read only decode part 4 for specifying an address in the array based on an address signal ADD, and a write only decode part 6. The input of both decode parts is shared, and a delay part (for example, a FIFO(first-in-first-one) memory 14) for delaying the addressing by the decode part by a specific time from the read only decode part side is provided, thereby RMW operation (data read/write and accompanying two addressings, etc.) can be done within one clock section. By switching the memory capacity of the FIFO memory 14 according to a pointer signal, a delay time can be changed. The delay part may be configured by a register. |
