When a particular GSx RAM block is owned by the CPU1 subsystem, CPU1 and CPU1.DMA have full access to that RAM block, whereas CPU2 and CPU2.DMA have only read access to it (no fetch/write access).
手册中是上面这样说的，如果把一块共享内存分配给cpu1的话，那么cpu2就是能read （不能fetch 和write），我想问一下，这个fetch和read有什么区别呢？
