Simplify Fixed point Math notations

src/main/common/maths.c

@@ -338,15 +338,14 @@ void arraySubInt32(int32_t *dest, int32_t *array1, int32_t *array2, int count)
     }
 }
 
-int16_t qPercent(q_number_t q) {
+int16_t qPercent(fix12_t q) {
-    return 100 * q.num / q.den;
+    return (100 * q) >> 12;
 }
 
-int16_t qMultiply(q_number_t q, int16_t input) {
+int16_t qMultiply(fix12_t q, int16_t input) {
-    return input *  q.num / q.den;
+    return (input *  q) >> 12;
 }
 
-void qConstruct(q_number_t *qNumber, int16_t num, int16_t den, int qType) {
+fix12_t  qConstruct(int16_t num, int16_t den) {
-    qNumber->num = (1 << qType) / den;
+    return (num << 12) / den;
-    qNumber->den = (1 << qType) / num;
 }

src/main/common/maths.h

@@ -34,28 +34,16 @@
 #define MAX(a, b) ((a) > (b) ? (a) : (b))
 #define ABS(x) ((x) > 0 ? (x) : -(x))
 
+#define Q12 (1 << 12)
+
+typedef int32_t fix12_t;
+
 typedef struct stdev_s
 {
     float m_oldM, m_newM, m_oldS, m_newS;
     int m_n;
 } stdev_t;
 
-#define Q12(x) ((1 << 12) / x)
-#define Q13(x) ((1 << 13) / x)
-#define Q14(x) ((1 << 14) / x)
-
-typedef enum {
-    Q12_NUMBER = 12,
-    Q13_NUMBER,
-    Q14_NUMBER
-} qTypeIndex_e;
-
-typedef struct q_number_s {
-    int16_t num;
-    int16_t den;
-} q_number_t;
-
-
 // Floating point 3 vector.
 typedef struct fp_vector {
     float X;
@@ -125,6 +113,6 @@ float acos_approx(float x);
 
 void arraySubInt32(int32_t *dest, int32_t *array1, int32_t *array2, int count);
 
-int16_t qPercent(q_number_t q);
+int16_t qPercent(fix12_t q);
-int16_t qMultiply(q_number_t q, int16_t input);
+int16_t qMultiply(fix12_t q, int16_t input);
-void qConstruct(q_number_t *qNumber, int16_t num, int16_t den, int qType);
+fix12_t qConstruct(int16_t num, int16_t den);

src/main/flight/mixer.c

@@ -753,7 +753,7 @@ void acroPlusApply(void) {
 
     for (axis = 0; axis < 2; axis++) {
         int16_t factor;
-        q_number_t wowFactor;
+        fix12_t wowFactor;
         int16_t rcCommandDeflection = constrain(rcCommand[axis], -500, 500); // Limit stick input to 500 (rcCommand 100)
         int16_t acroPlusStickOffset = rxConfig->acroPlusOffset * 5;
         int16_t motorRange = escAndServoConfig->maxthrottle - escAndServoConfig->minthrottle;
@@ -766,11 +766,11 @@ void acroPlusApply(void) {
             } else {
                 rcCommandDeflection += acroPlusStickOffset;
             }
-            qConstruct(&wowFactor,ABS(rcCommandDeflection) * rxConfig->acroPlusFactor / 100, 500, Q12_NUMBER);
+            wowFactor = qConstruct(ABS(rcCommandDeflection) * rxConfig->acroPlusFactor / 100, 500);
             factor = qMultiply(wowFactor, (rcCommandDeflection * motorRange) / 500);
-            wowFactor.num = wowFactor.den - wowFactor.num;
+            wowFactor = Q12 - wowFactor;
         } else {
-            qConstruct(&wowFactor, 1, 1, Q12_NUMBER);
+            wowFactor = Q12;
             factor = 0;
         }
         axisPID[axis] = factor + qMultiply(wowFactor, axisPID[axis]);
@@ -780,8 +780,8 @@ void acroPlusApply(void) {
 void mixTable(void)
 {
     uint32_t i;
-    q_number_t vbatCompensationFactor;
+    fix12_t vbatCompensationFactor;
-    static q_number_t mixReduction;
+    static fix12_t mixReduction;
     uint8_t axis;
 
     bool isFailsafeActive = failsafeIsActive(); // TODO - Find out if failsafe checks are really needed here in mixer code
@@ -857,7 +857,7 @@ void mixTable(void)
 
     if (rollPitchYawMixRange > throttleRange) {
         motorLimitReached = true;
-        qConstruct(&mixReduction, throttleRange, rollPitchYawMixRange, Q12_NUMBER);
+        mixReduction = qConstruct(throttleRange, rollPitchYawMixRange);
 
         for (i = 0; i < motorCount; i++) {
             rollPitchYawMix[i] =  qMultiply(mixReduction,rollPitchYawMix[i]);

src/main/sensors/battery.c

@@ -215,13 +215,13 @@ void updateCurrentMeter(int32_t lastUpdateAt, rxConfig_t *rxConfig, uint16_t dea
     mAhDrawn = mAhdrawnRaw / (3600 * 100);
 }
 
-q_number_t calculateVbatPidCompensation(void) {
+fix12_t calculateVbatPidCompensation(void) {
-	q_number_t batteryScaler;
+	fix12_t batteryScaler;
     if (batteryConfig->vbatPidCompensation && feature(FEATURE_VBAT) && batteryCellCount > 1) {
         uint16_t maxCalculatedVoltage = batteryConfig->vbatmaxcellvoltage * batteryCellCount;
-        qConstruct(&batteryScaler, maxCalculatedVoltage, constrain(vbat, maxCalculatedVoltage - batteryConfig->vbatmaxcellvoltage, maxCalculatedVoltage), Q12_NUMBER);
+        batteryScaler = qConstruct(maxCalculatedVoltage, constrain(vbat, maxCalculatedVoltage - batteryConfig->vbatmaxcellvoltage, maxCalculatedVoltage));
     } else {
-        qConstruct(&batteryScaler, 1, 1, Q12_NUMBER);
+        batteryScaler = Q12;
     }
 
     return batteryScaler;

src/main/sensors/battery.h

@@ -77,6 +77,6 @@ batteryConfig_t *batteryConfig;
 void updateCurrentMeter(int32_t lastUpdateAt, rxConfig_t *rxConfig, uint16_t deadband3d_throttle);
 int32_t currentMeterToCentiamps(uint16_t src);
 
-q_number_t calculateVbatPidCompensation(void);
+fix12_t calculateVbatPidCompensation(void);
 uint8_t calculateBatteryPercentage(void);
 uint8_t calculateBatteryCapacityRemainingPercentage(void);