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#include <math.h>
#include <stdio.h>
//#if 1 //(UGLY_IEEE754_FLOAT32_HACK :-)
/*
static inline float todB_a(const float *x){
return (float)((*(int *)x)&0x7fffffff) * 7.17711438e-7f -764.6161886f;
}
*/
static inline float todB_a(const float *x){
union {
//int32_t i;
int i;
float f;
} ix;
ix.f = *x;
ix.i = ix.i&0x7fffffff;
return (float)(ix.i * 7.17711438e-7f -764.6161886f);
}
//#else
static inline float todB_a2(const float *x){
return (*(x)==0?-400.f:logf(*(x)**(x))*4.34294480f);
}
//#endif
int main() {
float f, dbav[32]={0.f}, dbaf[32]={0.f};
int i=0;
for(f=1024000.f;f>1.f;f/=2.f) {
dbaf[31-i]=f;
dbav[31-i]=todB_a(&f);
i++;
}
for (i=0;i<32;i++)
printf("f==%f\tv==%f\n", dbaf[i], dbav[i]);
return 0;
}
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