Use of Sprintf increases code size!!

There are a variety of routines in the standard C library that convert strings to binary (atoi, strtol, sscanf). But there's a dearth of routines that go the other way, integer to string. Routiens like itoa() are common extensions, but not actually part of the C89 standard, and not supplied with the Keil libraries.

It's not that hard to write. Off the top of my head:

// do not call on empty strings; len must be >= 1
void StrReverse (char* s, U8 len)
    {
    char tmpChar;
    U8 i;

    for (i = 0; i < len / 2; ++i)
        {
        tmpChar = s[i];
        s[i] = s[len - 1 - i];
        s[len - 1 - i] = tmpChar;
        }

    } // StrReverse



U8 U16toString (U16 val, char* s)
    {
    U8 len;

    len = 0;
    do
        {
        s[len++] = '0' + val % 10;
        val /= 10;
        }
    while (val);
    s[len] = 0; // null terminate string

    StrReverse (s, len);

    return len;
    } // U16toString

You could also build the string most-significant-digit first, but it seemed to me like there would be a lot more division and multiplication involved that way, and that reversing the result would be faster.

(Once upon a time, probably years ago now, Jon Ward asked if there was any reason people would use both quotient and remainder of a mod operation. Here's another example where both are used. The compiler could usefully retain both results and avoid having to divide by ten twice.)

There are a variety of routines in the standard C library that convert strings to binary (atoi, strtol, sscanf). But there's a dearth of routines that go the other way, integer to string. Routiens like itoa() are common extensions, but not actually part of the C89 standard, and not supplied with the Keil libraries.

It's not that hard to write. Off the top of my head:

// do not call on empty strings; len must be >= 1
void StrReverse (char* s, U8 len)
    {
    char tmpChar;
    U8 i;

    for (i = 0; i < len / 2; ++i)
        {
        tmpChar = s[i];
        s[i] = s[len - 1 - i];
        s[len - 1 - i] = tmpChar;
        }

    } // StrReverse



U8 U16toString (U16 val, char* s)
    {
    U8 len;

    len = 0;
    do
        {
        s[len++] = '0' + val % 10;
        val /= 10;
        }
    while (val);
    s[len] = 0; // null terminate string

    StrReverse (s, len);

    return len;
    } // U16toString

You could also build the string most-significant-digit first, but it seemed to me like there would be a lot more division and multiplication involved that way, and that reversing the result would be faster.

(Once upon a time, probably years ago now, Jon Ward asked if there was any reason people would use both quotient and remainder of a mod operation. Here's another example where both are used. The compiler could usefully retain both results and avoid having to divide by ten twice.)