MSP430 IAR C/C++ Compiler reference guide - Rice University

The DLIB runtime environmentExample of using __write and __readThe code in the following examples use memory-mapped I/O to write to an LCDdisplay:__no_init volatile unsigned char LCD_IO @ address;size_t __write(int Handle, const unsigned char * Buf,size_t Bufsize){size_t nChars = 0;/* Check for stdout and stderr(only necessary if file descriptors are enabled.) */if (Handle != 1 && Handle != 2){return -1;}for (/*Empty */; Bufsize > 0; --Bufsize){LCD_IO = * Buf++;++nChars;}return nChars;}The code in the following example uses memory-mapped I/O to read from a keyboard:__no_init volatile unsigned char KB_IO @ 0xD2;size_t __read(int Handle, unsigned char *Buf, size_t BufSize){size_t nChars = 0;/* Check for stdin(only necessary if FILE descriptors are enabled) */if (Handle != 0){return -1;}for (/*Empty*/; BufSize > 0; --BufSize){unsigned char c = KB_IO;if (c == 0)break;*Buf++ = c;++nChars;}return nChars;}Part 1. Using the compiler61