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Re #3059: table lookup used for unit conversion, saved some 50 bytes of FLASH

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Damjan Adamic 2015-11-12 14:34:46 +01:00
parent 58edcc3af8
commit 454a664d01
1 changed files with 36 additions and 47 deletions
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83
radio/src/telemetry/telemetry.cpp
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@ -547,62 +547,51 @@ bool TelemetrySensor::isAvailable() const
return ZLEN(label) > 0;
}
PACK(typedef struct {
uint8_t unitFrom;
uint8_t unitTo;
int16_t multiplier;
int16_t divisor;
}) UnitConversionRule;
const UnitConversionRule unitConversionTable[] = {
/* unitFrom unitTo multiplier divisor */
{ UNIT_METERS, UNIT_FEET, 105, 32},
{ UNIT_METERS_PER_SECOND, UNIT_FEET_PER_SECOND, 105, 32},
{ UNIT_KTS, UNIT_KMH, 1852, 1000}, // 1 knot = 1.85200 kilometers per hour
{ UNIT_KTS, UNIT_MPH, 1151, 1000}, // 1 knot = 1.15077945 miles per hour
{ UNIT_KTS, UNIT_METERS_PER_SECOND, 1000, 1944}, // 1 knot = 0.514444444 meters / second (divide with 1.94384449)
{ UNIT_KTS, UNIT_FEET_PER_SECOND, 1688, 1000}, // 1 knot = 1.68780986 feet per second
{ UNIT_KMH, UNIT_KTS, 1000, 1852}, // 1 km/h = 0.539956803 knots (divide with 1.85200)
{ UNIT_KMH, UNIT_MPH, 1000, 1609}, // 1 km/h = 0.621371192 miles per hour (divide with 1.60934400)
{ UNIT_KMH, UNIT_METERS_PER_SECOND, 10, 36}, // 1 km/h = 0.277777778 meters / second (divide with 3.6)
{ UNIT_KMH, UNIT_FEET_PER_SECOND, 911, 1000}, // 1 km/h = 0.911344415 feet per second
{ UNIT_MILLILITERS, UNIT_FLOZ, 100, 2957},
{ 0, 0, 0, 0} // termination
};
int32_t convertTelemetryValue(int32_t value, uint8_t unit, uint8_t prec, uint8_t destUnit, uint8_t destPrec)
{
for (int i=prec; i<destPrec; i++)
value *= 10;
if (unit == UNIT_METERS || unit == UNIT_METERS_PER_SECOND) {
if (destUnit == UNIT_FEET || destUnit == UNIT_FEET_PER_SECOND) {
// m to ft *105/32
value = (value * 105) / 32;
}
}
else if (unit == UNIT_KTS) {
if (destUnit == UNIT_KMH) {
// 1 knot = 1.85200 kilometers per hour
value = (value * 1852) / 1000;
}
else if (destUnit == UNIT_MPH) {
// 1 knot = 1.15077945 miles per hour
value = (value * 1151) / 1000;
}
else if (destUnit == UNIT_METERS_PER_SECOND) {
// 1 knot = 0.514444444 meters / second (divide with 1.94384449)
value = (value * 1000) / 1944;
}
else if (destUnit == UNIT_FEET_PER_SECOND) {
// 1 knot = 1.68780986 feet per second
value = (value * 1688) / 1000;
}
}
else if (unit == UNIT_KMH) {
if (destUnit == UNIT_KTS) {
// 1 km/h = 0.539956803 knots (divide with 1.85200)
value = (value * 1000) / 1852;
}
else if (destUnit == UNIT_MPH) {
// 1 km/h = 0.621371192 miles per hour (divide with 1.60934400)
value = (value * 1000) / 1609;
}
else if (destUnit == UNIT_METERS_PER_SECOND) {
// 1 km/h = 0.277777778 meters / second (or beter division with 3.6)
value = (value * 1000) / 3600;
}
else if (destUnit == UNIT_FEET_PER_SECOND) {
// (1 km/h = 0.911344415 feet per second
value = (value * 911) / 1000;
}
}
else if (unit == UNIT_CELSIUS) {
if (unit == UNIT_CELSIUS) {
if (destUnit == UNIT_FAHRENHEIT) {
// T(°F) = T(°C)×1,8 + 32
value = 32 + (value*18)/10;
value = 32 + (value*18) / 10;
}
}
else if (unit == UNIT_MILLILITERS) {
if (destUnit == UNIT_FLOZ) {
value = (value * 100) / 2957;
else {
const UnitConversionRule * p = unitConversionTable;
while (p->divisor) {
if (p->unitFrom == unit && p->unitTo == destUnit) {
value = (value * (int32_t)p->multiplier) / (int32_t)p->divisor;
break;
}
++p;
}
}