Riot: 플로트와 더블이 곳곳에서 사용되고 있습니다.

설명

대부분의 플랫폼에는 단정밀도 부동 소수점에 대한 HW 지원이 없으며 (기본을 제외하고) 배정밀도를 지원하는 플랫폼은 없습니다.

grep 소스 코드를 통해 float 및 double의 인스턴스를 찾을 수 있습니다. 다음과 같은 이유로 문제가 됩니다.

• soft-float 지원이 연결되어야 하는 경우 코드 크기를 늘립니다.
• 소프트 플로트는 느립니다.
• 하드 플로트를 사용할 수 있는 경우에도 일반적으로 인터럽트 또는 커널 코드에서 사용하지 않아야 합니다. 이는 fp 레지스터 저장/복원과 관련되기 때문입니다.
  
  
  
  • 드라이버를 사용하면 어떤 컨텍스트에서 실행되는지 알기가 어렵습니다.
  
  
• 사용자는 예를 들어 sx127x 드라이버가 double을 사용하고 있는지 의심조차 할 수 없습니다.

내가 볼 때 이러한 사용의 대부분은 정당하지 않습니다. 특히 double의 _all_ 사용은 float로 대체될 수 있습니다.

문제를 재현하는 단계

대략적인 검색을 하는 빠른 방법은 다음 정규식을 사용하는 것입니다.

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

그들은 일부 거짓 긍정을 포착하고 일부 거짓 부정을 놓칠 것입니다.

실제 결과

수동 정리 후 결과는 다음과 같습니다.

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;

지금 무엇?

더블은 사라져야 합니다. 나는 그것이 아주 분명하다고 믿습니다.

센서 드라이버에는 부동 소수점이 사용됩니다. 이것은 내 생각에 잘못된 것입니다. 드라이버에는 장치에서 데이터 검색을 담당하는 계층이 있어야 합니다. 해당 계층은 부동 소수점 계산을 수행하는 업무가 없습니다. 어떤 경우에도 mpu9150과 같은 센서의 경우 정수 연산만을 사용하여 값을 완벽하게 표현하고 조작할 수 있는 경우에도 float가 필요하지 않습니다.