#include <stdio.h>
#include <stdint.h>
#include <math.h>

#ifdef AVR
#include <avr/pgmspace.h>
#define printf_PP(s, ...) printf_P(PSTR(s), ## __VA_ARGS__)
#else
#define printf_PP(s, ...) printf(s, ## __VA_ARGS__)
#endif

uint32_t AD8950_setting_integer(uint32_t f_osc,
        uint32_t f_tune_hz, uint32_t f_tune_millihz) {
    uint64_t tmp = (((uint64_t)f_tune_hz) << 32) + (f_osc+1)/2;
    tmp += ((((uint64_t)f_tune_millihz) << 32) + 500)/ 1000;
    return tmp / f_osc;
}

uint32_t AD8950_setting_fp(uint32_t f_osc,
        uint32_t f_tune_hz, uint32_t f_tune_millihz) {
    return (uint32_t)round((f_tune_hz + 1e-3 * f_tune_millihz)
            * 4294967296. / f_osc);
}


uint32_t AD8950_setting_integer(uint32_t f_osc, uint32_t f_tune) {
    uint64_t tmp = (((uint64_t)f_tune) << 32) + (f_osc+1)/2;
    return tmp / f_osc;
}

uint32_t AD8950_setting_fp(uint32_t f_osc, uint32_t f_tune) {
    return (uint32_t)round(f_tune * 4294967296. / f_osc);
}

uint32_t absdiff(uint32_t a, uint32_t b)
{
    if(a<b) return b-a;
    return a-b;
}

int main() {
    uint32_t osc_nom = 125000000.;

    printf_PP("60kHz for varying oscillator offsets:\n");
    printf_PP("osc_off    setting_int setting_fp\n");
    for(int32_t osc_off = -250; osc_off <= 250; osc_off += 50) {
        printf_PP("% 6d  %10lu  %10lu\n", (int)osc_off,
            (unsigned long)AD8950_setting_integer(osc_nom + osc_off, 60000),
            (unsigned long)AD8950_setting_fp(osc_nom + osc_off, 60000));
    }
    printf_PP("\n");

    printf_PP("60.000123kHz (60000.123Hz) for varying oscillator offsets:\n");
    printf_PP("osc_off    setting_int setting_fp\n");
    for(int32_t osc_off = -250; osc_off <= 250; osc_off += 50) {
        printf_PP("% 6d  %10lu  %10lu\n", (int)osc_off,
            (unsigned long)AD8950_setting_integer(osc_nom + osc_off, 60000, 123),
            (unsigned long)AD8950_setting_fp(osc_nom + osc_off, 60000, 123));
    }
    printf_PP("\n");

    printf_PP("1MHz for varying oscillator offsets:\n");
    printf_PP("osc_off   setting_int setting_fp\n");
    for(int32_t osc_off = -250; osc_off <= 250; osc_off += 50) {
        printf_PP("% 6d  %10lu  %10lu\n", (int)osc_off,
            (unsigned long)AD8950_setting_integer(osc_nom + osc_off, 1000000),
            (unsigned long)AD8950_setting_fp(osc_nom + osc_off, 1000000));
    }

    printf_PP("\nSearching for worst error ...\n");
    printf_PP("osc_off   freq          setting_int setting_fp setting_err\n");
    int32_t worst_off, worst_f, worst_err=0, n_err=0, n_tri=0;
    for(int32_t osc_off = -250; osc_off <= 250; osc_off += 3) {
        uint32_t osc = osc_nom + osc_off;
        for(uint32_t freq = 10000, freq_m=0; freq < osc/4; freq+=9, freq_m = (freq_m + 337) % 1000)
        {
            uint32_t setting_integer = AD8950_setting_integer(osc, freq, freq_m);
            uint32_t setting_fp = AD8950_setting_fp(osc, freq, freq_m);
            uint32_t err = absdiff(setting_integer, setting_fp);

            if(err > worst_err)
            {
                worst_off = osc_off;
                worst_f = freq;
                worst_err = err;
                n_err = 0;
            }
            if(worst_err && err == worst_err)
            {
                n_err ++;
                if(n_err < 10)
                    printf_PP("% 6d  %10lu.%03d %10lu  %10lu  %d\n",
                            (int)osc_off, (unsigned long)freq, (int) freq_m,
                            (unsigned long)setting_integer,
                            (unsigned long)setting_fp,
                            err);
                else if(n_err == 10)
                    printf_PP("...\n");
            }
            n_tri ++;
        }
    }
    printf_PP("worst error of %d counts", worst_err);
    printf_PP(" seen in %d of %d test cases\n", n_err, n_tri);
}