14 lines
335 B
C
14 lines
335 B
C
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#include "math.h"
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int64_t fsqrt64(int64_t a, unsigned int fracbits)
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{
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int64_t b = a/2 + (1 << fracbits); /* initial approximation */
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unsigned int n;
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const unsigned int iterations = 3; /* very rough approximation */
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for (n = 0; n < iterations; ++n)
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b = (b + (((int64_t)(a) << fracbits)/b))/2;
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return b;
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}
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