maybe.c

/**
 *
 */
static int insn_two_params(char **insn, struct insn_tbl *tbl)
{
    long number;
    char *nptr = NULL;
    char *p = *insn;

    /*
     * We already have the first register, let us check
     * if is correct.
     */
    if (tolower(*p) != 'r' || *(p+1) < '0' || *(p+1) > '7')
    {
        fprintf(stderr, "file.c:%d: Error: first operand '%c%c' of "
            "instruction '%s' is invalid!\n", 0, *p, *(p+1), tbl->name);
        return (-1);
    }

    p += 2;

    /* Skip white-spaces. */
    while (isblank(*p))
        p++;

    /* Check if separator exists. */
    if (*p != ',')
    {
        fprintf(stderr, "file.c:%d: Error: expected ',' found '%c'\n",
            0, *p);
        return (-1);
    }

    p++;

    /* Skip white-spaces again. */
    while (isblank(*p))
        p++;

    /*
     * If Reg/Reg
     */
    if (tolower(*p) == 'r')
    {
        if (*(p+1) < '0' || *(p+1) > '7')
        {
            fprintf(stderr, "file.c:%d: Error: second operand '%c%c' of "
                "instruction '%s' is invalid!\n", 0, *p, *(p+1), tbl->name);
            return (-1);
        }

        p += 2;

        /* Do something. */

        /* Skip white-spaces. */
        while (isblank(*p))
            p++;

        /* Check again. */
        if (*p != '#' && *p != ';' && *p != '\n' && *p != '\0')
        {
            fprintf(stderr, "file.c:%d Error: unexpected character (%c)!\n", 0, *p);
            return (-1);
        }
    }

    /* Reg/Imm. */
    else
    {
        nptr = NULL;
        number = strtol(p, &nptr, 0);
        if (p == nptr || errno != 0)
        {
            fprintf(stderr, "file.c:%d Error: second operand of"
                "instruction '%s' is invalid!\n", 0, tbl->name);
        }

        p = nptr;

        /* Skip white-spaces. */
        while (isblank(*p))
            p++;

        /* Check again. */
        if (*p != '#' && *p != ';' && *p != '\n' && *p != '\0')
        {
            fprintf(stderr, "file.c:%d Error: unexpected character (%c)!\n", 0, *p);
            return (-1);
        }

        if (*p == ';')
            p++;

        printf("p inside: %p / num: %ld\n", p, number);
    }

    /* Update the pointer. */
    *insn = p;

    return (0);
}