c - converting base 4 code to letters

Question

im working on an assmebler project that i have and i need to translate binary machine code that i have to a "weird" 4 base code for example if i get binary code like this "0000-10-01-00" i should translate it to "aacba"

00=a

01=b

10=c

11=d

i have managed to translate the code to 4 base code but i dont know how to continue from there or if this is the right way to do it,...

adding my code below

void intToBase4 (unsigned int *num)
{
  int d[7];
  int j,i=0;
  double x=0;
  while((*num)>0)
  {
    d[i]=(*num)%4;
    i++;
    (*num)=(*num)/4;
  }
  for(x=0,j=i-1; j>=0; j--)
  {
    x += d[j]*pow(10,j);
  }
  (*num)=(unsigned int)x;
}

Answer 1

I've included a little 32-bit to num to letter converter for you to grasp the basics. It works a single "32-bit number" at a time. You could use this as a basis for an array based solution like you have half way done in your example, or change the type to be bigger, or whatever. It should show you roughly what you need to do:

void intToBase4 (uint32_t num, char *outString)
{
  // There are 16 digits per num in this example
  for(int i=0; i<16; i++)
  { 
    // Grab the lowest 2 bits and convert to a letter.
    *outString++ = (num & 0x03) + 'a';

    // Shift next 2 bits low
    num >>= 2;
  }
  // NUL terminate string.
  *outString = '';
}