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#include "fix16.h"
#include "int64.h"
#ifndef FIXMATH_NO_CACHE
static fix16_t _fix16_exp_cache_index[4096] = { 0 };
static fix16_t _fix16_exp_cache_value[4096] = { 0 };
#endif
fix16_t fix16_exp(fix16_t inValue) {
if(inValue == 0)
return fix16_one;
if(inValue == fix16_one)
return fix16_e;
if(inValue > 681391)
return fix16_max;
if(inValue < -726817)
return 0;
#ifndef FIXMATH_NO_CACHE
fix16_t tempIndex = (inValue ^ (inValue >> 16));
tempIndex = (inValue ^ (inValue >> 4)) & 0x0FFF;
if(_fix16_exp_cache_index[tempIndex] == inValue)
return _fix16_exp_cache_value[tempIndex];
#endif
int64_t tempOut = int64_add(int64_from_int32(fix16_one), int64_from_int32(inValue));
int64_t tempValue = int64_from_int32(inValue);
uint32_t i, n;
for(i = 3, n = 2; i < 13; n *= i, i++) {
tempValue = int64_mul_i64_i32(tempValue, inValue);
#ifndef FIXMATH_NO_ROUNDING
tempValue = int64_add(tempValue, int64_from_int32(fix16_one >> 1));
#endif
tempValue = int64_shift(tempValue, -16);
tempOut = int64_add(tempOut, int64_div_i64_i32(tempValue, n));
}
#ifndef FIXMATH_NO_CACHE
_fix16_exp_cache_index[tempIndex] = inValue;
_fix16_exp_cache_value[tempIndex] = int64_lo(tempOut);
#endif
return int64_lo(tempOut);
}
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