Binary2BCD

/* Converte número binário (unsigned) 16-bit no seu equivalente decimal (formato BCD compactado). */


// Apple Xcode
//
//  main.c
//
//  Created by Paulo G.P. on 6/27/11.
//

#include <stdio.h>


void adjust(unsigned char *p)
{
    unsigned char t = *p + 3;
    if (t & 0x08) *p = t;
    t = *p + 0x30;
    if (t & 0x80) *p = t;
}

unsigned long binary2bcd(unsigned int n)
{
    unsigned char bcd[3] = {0, 0, 0};

    for (int i = 0; i < 16; ++i) {
        adjust(&bcd[0]);
        adjust(&bcd[1]);
        adjust(&bcd[2]);

        bcd[2] <<= 1;
        if (bcd[1] & 0x80) ++bcd[2];

        bcd[1] <<= 1;
        if (bcd[0] & 0x80) ++bcd[1];

        bcd[0] <<= 1;
        if (n & 0x8000) ++bcd[0];

        n <<= 1;
    }

    return (unsigned long)(bcd[2] << 16) | (bcd[1] << 8) | bcd[0];
}

int main (int argc, const char * argv[])
{
    int the_example = 10;

    printf("resultado: %lu\n", binary2bcd(the_example));

    return 0;
}