HelenOS sources

omap_uart_txb      60 kernel/genarch/src/drivers/omap/uart.c 			omap_uart_txb(uart, '\r');
omap_uart_txb      62 kernel/genarch/src/drivers/omap/uart.c 		omap_uart_txb(uart, (uint8_t) *s);
HelenOS homepage, sources at GitHub