memx_cmd
memx_cmd(memx, MEMX_WR32, 2, (u32[]){ addr, data });
memx_cmd(memx, MEMX_WAIT, 4, (u32[]){ addr, mask, data, nsec });
memx_cmd(memx, MEMX_DELAY, 1, (u32[]){ nsec });
memx_cmd(memx, MEMX_VBLANK, 1, (u32[]){ head_sync });
memx_cmd(memx, MEMX_TRAIN, 0, NULL);
memx_cmd(memx, MEMX_ENTER, 0, NULL);
memx_cmd(memx, MEMX_LEAVE, 0, NULL);