hamule/gainmargin.c at main · LightningStalker/hamule · GitHub

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/* Compile with gcc -Wall -o gainmargin gainmargin.c -lm
    From STMicroelectronics AN2867 Rev 20 p.13
    Project Crew 2024 */

#if defined (__WATCOMC__)
#define PROGNAME "gainmarg"
#elif defined (__GNUC__)
#define PROGNAME "gainmargin"
#endif

#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#if defined (__GNUC__)
#include <locale.h>
#endif

#if defined (__DOS__)
#define SUBM   "(m)"
#else
#define SUBM   "ₘ"                     /* differences of the codepage */
#endif


int main (int argc, char **argv)
{
#if defined (__GNUC__)
    unsetenv ("LC_ALL");
    setlocale (LC_NUMERIC, "");  // This should give us digit grouping
#endif

    if (argc == 5)
    {
#if defined (__WATCOMC__)
        printf ("%.5LfmA/V\n",
                4e3 * atoll(argv[3]) *
                pow(2 * M_PI * atoll(argv[4]) * 1e6, 2) *
                pow((atoll(argv[1]) + atoll(argv[2])) * 1e-12, 2)
            );
#elif defined (__GNUC__)
        printf ("%'.5LfmA/V\n",
                4e3 * atoll(argv[3]) *
                powl(2 * M_PI * atoll(argv[4]) * 1e6, 2) *
                powl((atoll(argv[1]) + atoll(argv[2])) * 1e-12, 2)
            );
#endif
        return (0);
    }
    else
    {
        puts ( \
            "\n"
            "  "PROGNAME" is a critical gain margin calculator for crystal oscillators.\n"
            "  output is g"SUBM"crit in mA/V\n"
            "\n"
            "  Usage: "PROGNAME" shunt_pF load_pF ESR MHz\n"
            "  Example: "PROGNAME" 5.0 12.0 150.0 12.0\n"
            "  Output should be: 0.98576mA/V\n"
            );

        return (EXIT_FAILURE);
    }
}