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lh3/fast-sqrtf.c

Created August 24, 2019 00:58
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Fast square root
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fast-sqrtf.c
// a combination of inverse square root (see wiki) and inversion: https://bits.stephan-brumme.com/inverse.html
static inline float mg_sqrtf(float x)
{
union { float f; uint32_t i; } z = { x };
z.i = 0x5f3759df - (z.i >> 1);
z.f *= (1.5f - (x * 0.5f * z.f * z.f));
z.i = 0x7EEEEEEE - z.i;
return z.f;
}
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