Riot: Floats und Doubles werden überall verwendet.

Beschreibung

Die meisten Plattformen haben keine HW-Unterstützung für Gleitkommazahlen mit einfacher Genauigkeit und keine (außer native) unterstützen die doppelte Genauigkeit.

grep Durchsuchen des Quellcodes kann ich Instanzen von float und double finden. Diese sind ein Problem, weil:

• Sie erhöhen die Codegröße, wenn Soft-Float-Unterstützung eingebunden werden muss.
• Weicher Schwimmer ist langsam.
• Auch wenn Hardfloat verfügbar ist, sollte es normalerweise nicht in Interrupts oder Kernel-Code verwendet werden, da dies das Speichern/Wiederherstellen von fp-Registern erfordern würde.
  
  
  
  • Bei Treibern ist schwer zu erkennen, was in welchem ​​Kontext läuft.
  
  
• Der Benutzer darf nicht einmal vermuten, dass beispielsweise der sx127x Treiber Doubles verwendet.

Soweit ich sehen kann, sind die meisten dieser Verwendungen ungerechtfertigt. Insbesondere könnten _alle_ Verwendungen von double durch float ersetzt werden.

Schritte zum Reproduzieren des Problems

Eine schnelle Möglichkeit, eine ungefähre Suche zu erhalten, besteht darin, diese Regexes zu verwenden:

$ git grep  "^\([^/]\|\(/[^*/]\)\)*\bdouble\b"  -- "*.[ch]"
$ git grep  "^\([^/]\|\(/[^*/]\)\)*\bfloat\b"  -- "*.[ch]"

Sie werden einige falsch positive Ergebnisse erkennen und wahrscheinlich einige falsch negative Ergebnisse übersehen.

Tatsächliche Ergebnisse

Nach einigen manuellen Bereinigungen sind hier die Ergebnisse:

drivers/bmp180/bmp180.c:    return (int16_t)(44330.0 * (1.0 - pow((double)p / pressure_0, 0.1903)));;
drivers/bmp180/bmp180.c:    return (uint32_t)((double)p / pow(1.0 - (altitude / 44330.0), 5.255));;
drivers/sx127x/sx127x_getset.c:    channel = (uint32_t)((double) channel / (double)LORA_FREQUENCY_RESOLUTION_DEFAULT);
drivers/sx127x/sx127x_getset.c:            double bw = 0.0;
drivers/sx127x/sx127x_getset.c:            double rs = bw / (1 << dev->settings.lora.datarate);
drivers/sx127x/sx127x_getset.c:            double ts = 1 / rs;
drivers/sx127x/sx127x_getset.c:            double t_preamble = (dev->settings.lora.preamble_len + 4.25) * ts;
drivers/sx127x/sx127x_getset.c:            double tmp =
drivers/sx127x/sx127x_getset.c:                    / (double) (4 * dev->settings.lora.datarate
drivers/sx127x/sx127x_getset.c:            double n_payload = 8 + ((tmp > 0) ? tmp : 0);
drivers/sx127x/sx127x_getset.c:            double t_payload = n_payload * ts;
drivers/sx127x/sx127x_getset.c:            double t_on_air = t_preamble + t_payload;
drivers/sx127x/sx127x_internal.c:    initial_freq = (double) (((uint32_t) sx127x_reg_read(dev, SX127X_REG_FRFMSB) << 16)
drivers/sx127x/sx127x_internal.c:                             | ((uint32_t) sx127x_reg_read(dev, SX127X_REG_FRFLSB))) * (double)LORA_FREQUENCY_RESOLUTION_DEFAULT;
drivers/tmp006/tmp006.c:    *tamb = (double)rawt / 128.0;
drivers/tmp006/tmp006.c:    double tdie_k = *tamb + 273.15;
drivers/tmp006/tmp006.c:    double sens_v = (double)rawv * TMP006_CCONST_LSB_SIZE;
drivers/tmp006/tmp006.c:    double tdiff = tdie_k - TMP006_CCONST_TREF;
drivers/tmp006/tmp006.c:    double tdiff_pow2 = pow(tdiff, 2);
drivers/tmp006/tmp006.c:    double s = TMP006_CCONST_S0 * (1 + TMP006_CCONST_A1 * tdiff
drivers/tmp006/tmp006.c:    double v_os = TMP006_CCONST_B0 + TMP006_CCONST_B1 * tdiff
drivers/tmp006/tmp006.c:    double f_obj = (sens_v - v_os) + TMP006_CCONST_C2 * pow((sens_v - v_os), 2);
drivers/tmp006/tmp006.c:    double t = pow(pow(tdie_k, 4) + (f_obj / s), 0.25);
sys/crypto/modes/ocb.c:       L_$ = double(L_*)
sys/crypto/modes/ocb.c:       L_0 = double(L_$)
sys/crypto/modes/ocb.c:       L_i = double(L_{i-1}) for every integer i > 0
sys/include/cb_mux.h: * @param[in] head   double pointer to first list entry
sys/include/cb_mux.h: * @param[in] head   double pointer to first list entry
sys/include/net/gnrc/rpl/structs.h:    double link_metric;             /**< metric of the link */
sys/include/random.h:double random_real(void);
sys/include/random.h:double random_real_inclusive(void);
sys/include/random.h:double random_real_exclusive(void);
sys/include/random.h:double random_res53(void);
sys/include/ubjson.h:static inline ssize_t ubjson_get_double(ubjson_cookie_t *__restrict cookie, ssize_t content, double *dest)
sys/include/ubjson.h:        double f;
sys/include/ubjson.h:ssize_t ubjson_write_double(ubjson_cookie_t *__restrict cookie, double value);
sys/net/routing/nhdp/iib_table.c:static const double const_dat = (((double)DAT_CONSTANT) / DAT_MAXIMUM_LOSS);
sys/net/routing/nhdp/iib_table.c:    double sum_total, sum_rcvd, loss;
sys/net/routing/nhdp/iib_table.c:                loss = (((double)ls_elt->hello_interval) * ((double)ls_elt->lost_hellos))
sys/quad_math/fixdfdi.c:quad_t __fixdfdi(double x)
sys/quad_math/fixunsdfdi.c:u_quad_t __fixunsdfdi(double x)
sys/quad_math/fixunssfdi.c:    double x, toppart;
sys/quad_math/fixunssfdi.c:    x -= (double) t.uq;
sys/quad_math/floatdidf.c:double __floatdidf(quad_t x)
sys/quad_math/floatdidf.c:    double d;
sys/quad_math/floatdidf.c:    d = (double) u.ul[H] * (((int) 1 << (INT_BITS - 2)) * 4.0);
sys/quad_math/floatdisf.c:    f = (double) u.ul[H] * (((int) 1 << (INT_BITS - 2)) * 4.0);
sys/quad_math/floatunsdidf.c:double __floatunsdidf(u_quad_t x)
sys/quad_math/floatunsdidf.c:    double d;
sys/quad_math/floatunsdidf.c:    d = (double) u.ul[H] * (((int) 1 << (INT_BITS - 2)) * 4.0);
sys/quad_math/quad.h:quad_t __fixdfdi(double);
sys/quad_math/quad.h:u_quad_t __fixunsdfdi(double);
sys/quad_math/quad.h:double __floatdidf(quad_t);
sys/quad_math/quad.h:double __floatunsdidf(u_quad_t);
sys/random/mersenne.c:double random_real(void)
sys/random/mersenne.c:double random_real_inclusive(void)
sys/random/mersenne.c:double random_real_exclusive(void)
sys/random/mersenne.c:    return ((double) random_uint32() + 0.5) * (1.0 / TWO_POW_32);
sys/random/mersenne.c:double random_res53(void)
sys/random/mersenne.c:    double a = random_uint32() * TWO_POW_26;
sys/random/mersenne.c:    double b = random_uint32() * (1.0 / TWO_POW_6);
sys/random/tinymt32/tinymt32.h:static inline double tinymt32_generate_32double(tinymt32_t *random)
sys/ubjson/ubjson-write.c:ssize_t ubjson_write_double(ubjson_cookie_t *restrict cookie, double value)
sys/ubjson/ubjson-write.c:        double f;
tests/bloom_bytes/main.c:    double false_positive_rate = (double) in / (double) lenA;
tests/float/main.c:    double x = 1234567.0 / 1024.0;
tests/float/main.c:        double z = (x - floor(x));
tests/thread_float/main.c:        printf("T(%" PRIkernel_pid "): %f\n", thread_getpid(), (double)f);
tests/unittests/tests-bloom/tests-bloom.c:    double false_positive_rate = 0;
tests/unittests/tests-bloom/tests-bloom.c:    false_positive_rate = (double) in / (double) lenA;
tests/unittests/tests-printf_float/tests-printf_float.c:static const double in0 = 2016.0349;
tests/unittests/tests-printf_float/tests-printf_float.c:static const double in1 = 123.4567;
tests/unittests/tests-printf_float/tests-printf_float.c:static const double in2 = 0.0;
tests/unittests/tests-sht1x/tests-sht1x.c:    static const double d1_table[] = { -40.1, -39.8, -39.7, -39.6, -39.4 };
tests/unittests/tests-sht1x/tests-sht1x.c:    double d1 = d1_table[dev->vdd];
tests/unittests/tests-sht1x/tests-sht1x.c:    double d2 = (dev->conf & SHT1X_CONF_LOW_RESOLUTION) ? 0.04 : 0.01;
tests/unittests/tests-sht1x/tests-sht1x.c:    double raw = (double)_raw;
tests/unittests/tests-sht1x/tests-sht1x.c:    double temp = d1 + d2 * raw;
tests/unittests/tests-sht1x/tests-sht1x.c:    static const double c1 = -2.0468;
tests/unittests/tests-sht1x/tests-sht1x.c:    static const double t1 = 0.01;
tests/unittests/tests-sht1x/tests-sht1x.c:    double temp = ((double)_temp) / 100.0;
tests/unittests/tests-sht1x/tests-sht1x.c:    double raw = (double)_raw;
tests/unittests/tests-sht1x/tests-sht1x.c:    double c2, c3, t2, hum_linear, hum_real;

cpu/esp32/vendor/esp-idf/include/esp32/esp_mesh.h:    float percentage;           /**< vote percentage threshold for approval of being a root */
cpu/esp32/vendor/esp-idf/include/esp32/esp_mesh.h:esp_err_t esp_mesh_set_vote_percentage(float percentage);
cpu/esp32/vendor/esp-idf/include/esp32/esp_mesh.h:float esp_mesh_get_vote_percentage(void);
cpu/esp8266/vendor/esp/phy_info.c:           (float)info->spur_freq_primary / info->spur_freq_divisor,
cpu/esp8266/vendor/esp/phy_info.c:           (float)info->spur_freq_2_primary / info->spur_freq_2_divisor,
cpu/esp8266/vendor/espressif/c_types.h:typedef float               real32_t;
cpu/esp8266/vendor/espressif/c_types.h:typedef float               real32;
drivers/adt7310/adt7310.c:#define ADT7310_TEMPERATURE_LSB_FLOAT (1.f/((float)((int)1 << ADT7310_VALUE_FRAC_BITS)))
drivers/adt7310/adt7310.c:float adt7310_read_float(const adt7310_t *dev)
drivers/adt7310/adt7310.c:    return (((float) raw) * ADT7310_TEMPERATURE_LSB_FLOAT);
drivers/at30tse75x/at30tse75x.c:static inline float temperature_to_float(uint16_t temp)
drivers/at30tse75x/at30tse75x.c:int at30tse75x_get_temperature(const at30tse75x_t *dev, float *temperature)
drivers/hih6130/hih6130.c:    float *relative_humidity_percent, float *temperature_celsius)
drivers/include/adt7310.h:float adt7310_read_float(const adt7310_t *dev);
drivers/include/at30tse75x.h:int at30tse75x_get_temperature(const at30tse75x_t* dev, float* temperature);
drivers/include/hih6130.h:    float *relative_humidity_percent, float *temperature_celsius);
drivers/include/isl29020.h:    float lux_fac;              /**< factor to calculate actual lux value */
drivers/include/isl29125.h:    float red;              /**< red lux value */
drivers/include/isl29125.h:    float green;            /**< green lux value */
drivers/include/isl29125.h:    float blue;             /**< blue lux value */
drivers/include/tmp006.h:void tmp006_convert(int16_t rawv, int16_t rawt,  float *tamb, float *tobj);
drivers/io1_xplained/io1_xplained_saul.c:static float temperature;
drivers/isl29020/isl29020.c:    dev->lux_fac = (float)((1 << (10 + (2 * DEV_RANGE))) - 1) / 0xffff;
drivers/isl29125/isl29125.c:    float luxfactor = (DEV_RANGE == ISL29125_RANGE_10K) ? 10000.0 / 65535.0 : 375.0 / 65535.0;
drivers/lpsxxx/lpsxxx.c:    float res = TEMP_BASE;      /* reference value -> see datasheet */
drivers/lpsxxx/lpsxxx.c:    res += ((float)val) / TEMP_DIVIDER;
drivers/mpu9150/mpu9150.c:    float fsr;
drivers/mpu9150/mpu9150.c:    float fsr;
drivers/mpu9150/mpu9150.c:    output->x_axis = (int16_t) (((float)output->x_axis) *
drivers/mpu9150/mpu9150.c:    output->y_axis = (int16_t) (((float)output->y_axis) *
drivers/mpu9150/mpu9150.c:    output->z_axis = (int16_t) (((float)output->z_axis) *
drivers/mq3/mq3.c:    float res = mq3_read_raw(dev);
drivers/tmp006/tmp006.c:void tmp006_convert(int16_t rawv, int16_t rawt,  float *tamb, float *tobj)
drivers/tmp006/tmp006.c:    float tamb, tobj;
sys/analog_util/adc_util.c:float adc_util_mapf(int sample, adc_res_t res, float min, float max)
sys/analog_util/dac_util.c:uint16_t dac_util_mapf(float value, float min, float max)
sys/color/color.c:    float rd, gd, bd, delta;
sys/color/color.c:    rd = (float)rgb->r / 255.0f;
sys/color/color.c:    gd = (float)rgb->g / 255.0f;
sys/color/color.c:    bd = (float)rgb->b / 255.0f;
sys/color/color.c:        float rc, gc, bc;
sys/color/color.c:    float aa, bb, cc, f, h;
sys/fmt/fmt.c:size_t fmt_float(char *out, float f, unsigned precision)
sys/fmt/fmt.c:void print_float(float f, unsigned precision)
sys/include/analog_util.h:float adc_util_mapf(int sample, adc_res_t res, float min, float max);
sys/include/analog_util.h:uint16_t dac_util_mapf(float value, float min, float max);
sys/include/color.h:    float h;            /**< hue value        [0.0 - 360.0] */
sys/include/color.h:    float s;            /**< saturation value [0.0 - 1.0] */
sys/include/color.h:    float v;            /**< value            [0.0 - 1.0] */
sys/include/ubjson.h:static inline ssize_t ubjson_get_float(ubjson_cookie_t *__restrict cookie, ssize_t content, float *dest)
sys/include/ubjson.h:        float f;
sys/include/ubjson.h:ssize_t ubjson_write_float(ubjson_cookie_t *__restrict cookie, float value);
sys/quad_math/fixsfdi.c:quad_t __fixsfdi(float x)
sys/quad_math/fixunssfdi.c:u_quad_t __fixunssfdi(float f)
sys/quad_math/floatdisf.c:float __floatdisf(quad_t x)
sys/quad_math/floatdisf.c:    float f;
sys/quad_math/quad.h:quad_t __fixsfdi(float);
sys/quad_math/quad.h:u_quad_t __fixunssfdi(float);
sys/quad_math/quad.h:float __floatdisf(quad_t);
sys/random/tinymt32/tinymt32.h:static inline float tinymt32_temper_conv(tinymt32_t *random)
sys/random/tinymt32/tinymt32.h:        float f;
sys/random/tinymt32/tinymt32.h:static inline float tinymt32_temper_conv_open(tinymt32_t *random)
sys/random/tinymt32/tinymt32.h:        float f;
sys/random/tinymt32/tinymt32.h:static inline float tinymt32_generate_float(tinymt32_t *random)
sys/random/tinymt32/tinymt32.h:static inline float tinymt32_generate_float12(tinymt32_t *random)
sys/random/tinymt32/tinymt32.h:static inline float tinymt32_generate_float01(tinymt32_t *random)
sys/random/tinymt32/tinymt32.h:static inline float tinymt32_generate_floatOC(tinymt32_t *random)
sys/random/tinymt32/tinymt32.h:static inline float tinymt32_generate_floatOO(tinymt32_t *random)
sys/shell/commands/sc_at30tse75x.c:            float temperature;
sys/ubjson/ubjson-write.c:ssize_t ubjson_write_float(ubjson_cookie_t *restrict cookie, float value)
sys/ubjson/ubjson-write.c:        float f;
tests/driver_adt7310/main.c:    float celsius_float;
tests/driver_adt7310/main.c:    float integral = 0;
tests/driver_adt7310/main.c:    float fractional;
tests/driver_hih6130/main.c:        float hum = 0.f;
tests/driver_hih6130/main.c:        float temp = 0.f;
tests/driver_hih6130/main.c:        float integral = 0.f;
tests/driver_hih6130/main.c:        float fractional;
tests/driver_io1_xplained/main.c:    float temperature;
tests/driver_tmp006/main.c:    float tamb, tobj;
tests/pkg_cmsis-dsp/main.c:    float int_part;
tests/pkg_cmsis-dsp/main.c:    float frac_part = fabsf(modff(variance, &int_part));
tests/rng/test.c:    float entropy = 0.0;
tests/rng/test.c:            float count = (float) buffer[i] / (float) length;
tests/rng/test.h:#define log2f(x) (logf (x) / (float) 0.693147180559945309417)
tests/thread_float/main.c:    float f, init;
tests/thread_float/main.c:    float f, init;
tests/unittests/tests-scanf_float/tests-scanf_float.c:    float x = 0;\
tests/unittests/tests-scanf_float/tests-scanf_float.c:    float x = 0;
tests/unittests/tests-scanf_float/tests-scanf_float.c:    float x = 0;

Was jetzt?

Die Doppel sollten verschwinden. Ich glaube, das ist ziemlich klar.

Es gibt Float-Verwendung in Sensortreibern. Dies ist meiner Meinung nach falsch. Der Treiber sollte eine Schicht haben, die für das Abrufen von Daten vom Gerät verantwortlich ist. Diese Schicht hat nichts mit Gleitkommaberechnungen zu tun. Auf jeden Fall wird der Float auch bei Sensoren wie dem mpu9150 nicht benötigt, bei denen Werte ausschließlich mit Integer-Mathematik perfekt ausgedrückt und manipuliert werden können.