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serial.c

#include <pxa250regs.S>
#include <stdarg.h>
#include "serial.h"

void serial_send_byte(int byte)
{
        volatile int * const lsr= (volatile int *)(FFUART_BASE+UART_LSR);
        volatile int * const thr= (volatile int *)(FFUART_BASE+UART_THR);

        while (((*lsr) & SIO_LSR_THRE) == 0) ;

        *thr = byte;
}

int printf(const char *format, ...)
{
        va_list ap;
        char c;

        va_start(ap, format);
        while (1)
        {
                c=*format;
                switch (c)
                {
                        // end of string
                        case 0:
                        {
                                goto stopPrintf;
                        }
                        break;

                        // special char
                        case '%':
                        {
                                c=*(++format);
                                switch (c)
                                {
                                        // end of string
                                        case 0:
                                        {
                                                goto stopPrintf;
                                        }
                                        break;

                                        // display %
                                        case '%':
                                        {
                                                serial_send_byte('%');
                                        }
                                        break;

                                        // char
                                        case 'c':
                                        {
                                                char typeC=va_arg(ap, int);
                                                serial_send_byte(typeC);
                                        }
                                        break;

                                        // string
                                        case 's':
                                        {
                                                char *typeCP=va_arg(ap, char *);
                                                if (typeCP)
                                                {
                                                        while (*typeCP)
                                                        {
                                                                serial_send_byte(*typeCP);
                                                                typeCP++;
                                                        }
                                                }
                                                else
                                                {
                                                        serial_send_byte('n');
                                                        serial_send_byte('u');
                                                        serial_send_byte('l');
                                                        serial_send_byte('l');
                                                }
                                        }
                                        break;

                                        // hexadecimal unsigned int
                                        case 'x':
                                        case 'X':
                                        {
                                                int i, v;
                                                unsigned int typeUI=va_arg(ap, unsigned int);
                                                char baseChar;
                                                if (c=='x')
                                                        baseChar='a';
                                                else
                                                        baseChar='A';
                                                for (i=28; i>=0; i-=4)
                                                {
                                                        v=(typeUI>>i)&0xF;
                                                        serial_send_byte(v < 10 ? ('0'+v) : (baseChar+(v-10)));
                                                }
                                        }
                                        break;

                                        // binary
                                        case 'b':
                                        {
                                                int i, v;
                                                unsigned int typeB=va_arg(ap, unsigned int);
                                                for (i=31; i>=0; i--)
                                                {
                                                        v=(typeB>>i)&0x1;
                                                        serial_send_byte(v == 1 ? '1' : '0');
                                                }
                                        }
                                        break;

                                        // decimal unsigned int
                                        case 'u':
                                        {
                                                unsigned int typeUI=va_arg(ap, unsigned int);
                                                unsigned int div;
                                                int hasPut=0;
                                                for (div=1000000000; div>0; div/=10)
                                                {
                                                        unsigned int aff=typeUI/div;
                                                        typeUI%=div;

                                                        if ((aff!=0) || (hasPut))
                                                        {
                                                                hasPut=1;
                                                                serial_send_byte('0'+aff);
                                                        }
                                                }
                                                if (!hasPut)
                                                        serial_send_byte('0');
                                        }
                                        break;

                                        // decimal signed int
                                        case 'd':
                                        {
                                                int typeI=va_arg(ap, int);
                                                unsigned int vAbs;
                                                unsigned int div;
                                                int hasPut=0;
                                                if (typeI<0)
                                                {
                                                        vAbs=(unsigned)(-typeI);
                                                        serial_send_byte('-');
                                                }
                                                else
                                                {
                                                        vAbs=(unsigned)typeI;
                                                }
                                                for (div=1000000000; div>0; div/=10)
                                                {
                                                        unsigned int aff=vAbs/div;
                                                        vAbs%=div;

                                                        if ((aff!=0) || (hasPut))
                                                        {
                                                                hasPut=1;
                                                                serial_send_byte('0'+aff);
                                                        }
                                                }
                                                if (!hasPut)
                                                        serial_send_byte('0');
                                        }
                                        break;

                                        // display char if not handled
                                        default:
                                        {
                                                serial_send_byte(c);
                                        }
                                        break;
                                }
                        }
                        break;

                        // other
                        default:
                        {
                                serial_send_byte(c);
                        }
                        break;
                }
                format++;
        }

// clean stack and return
stopPrintf:
        va_end(ap);

        // TODO : return number of printed character
        return 0;
}

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