what does this code mean in the context of a function: (*(volatile unsigned long *)(spi_base[dev] + SSP_CR0)) = buf;
1. buf is already defined as: unsigned int buf 2. spi_base is defined as: const unsigned long spi_base[MAX_SPI] = {SSP0_BASE_ADDR,SSP1_BASE_ADDR}; 3. SSP_CR0 as: #define SSP_CR0 0x00
which is what?