Where can i find the prototype of IOWR(base, ALTERA_AVALON_UART_RXDATA_REG,data)?

Hi, all

During the APP software developing based on NiosII cpu SOPC system, I can call the function IOWR_ALTERA_AVALON_UART_RXDATA(base, data) based on the macro-definition in xxx_BSP/driver/inc/altera_avalon_uart_regs.h.

The macro-definition is followed:

# define IOWR_ALTERA_AVALON_UART_RXDATA(base, data)

IOWR(base, ALTERA_AVALON_UART_RXDATA_REG, data)

My trouble is where can i find the prototype of IOWR(base,

ALTERA_AVALON_UART_RXDATA_REG, data) ?

It is appreciated to reply with key!