update veml7700 libary

smcallis77 · May 24, 2020 · e1e604e · e1e604e
1 parent ebbbd37
commit e1e604e
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Showing 2 changed files with 2 additions and 25 deletions.
diff --git a/lib/Adafruit_VEML7700/Adafruit_VEML7700.cpp b/lib/Adafruit_VEML7700/Adafruit_VEML7700.cpp
@@ -76,30 +76,6 @@ boolean Adafruit_VEML7700::begin(TwoWire *theWire) {
   return true;
 }
 
-float Adafruit_VEML7700::alternate_pow(float a, float b)
-{
-  // https://martin.ankerl.com/2012/01/25/optimized-approximative-pow-in-c-and-cpp/
-  // calculate approximation with fraction of the exponent
-  int e = abs((int)b);
-  union {
-    double d;
-    int x[2];
-  } u = { a };
-  u.x[1] = (int)((b - e) * (u.x[1] - 1072632447) + 1072632447);
-  u.x[0] = 0;
-  // exponentiation by squaring with the exponent's integer part
-  // double r = u.d makes everything much slower, not sure why
-  double r = 1.0;
-  while (e) {
-    if (e & 1) {
-      r *= a;
-    }
-    a *= a;
-    e >>= 1;
-  }
-  return r * u.d;
-}
-
 float Adafruit_VEML7700::normalize_resolution(float value) {
   // adjust for gain (1x is normalized)
   switch (getGain()) {

diff --git a/lib/Adafruit_VEML7700/Adafruit_VEML7700.h b/lib/Adafruit_VEML7700/Adafruit_VEML7700.h
@@ -62,6 +62,7 @@
 #define VEML7700_POWERSAVE_MODE3    0x02  ///< Power saving mode 3
 #define VEML7700_POWERSAVE_MODE4    0x03  ///< Power saving mode 4
 
+extern float FastPrecisePowf(const float x, const float y);
 
 /*!
  *    @brief  Class that stores state and functions for interacting with
@@ -110,7 +111,7 @@ class Adafruit_VEML7700 {
     *PowerSave_Enable, *PowerSave_Mode;
 
   float normalize_resolution(float value);
-  float alternate_pow(float a, float b);
+  static inline float alternate_pow(float a, float b) { return FastPrecisePowf(a, b); }
 
   Adafruit_I2CDevice *i2c_dev;