35 lines
614 B
C
35 lines
614 B
C
#ifndef _HELPERS_H_
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#define _HELPERS_H
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/*
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iLog, pow and root functions, taken from
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http://rosettacode.org/wiki/Nth_root#C
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*/
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float _fpow(float x, int e) {
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int i;
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float r = 1;
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for (i = 0; i < e; i++) {
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r *= x;
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}
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return r;
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}
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float _fsqrt(float x, int n) {
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float d, r = 1;
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if (!x) {
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return 0;
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}
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if (n < 1 || (x < 0 && !(n&1))) {
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return 0.0 / 0.0; /* NaN */
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}
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do {
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d = (x / _fpow(r, n - 1) - r) / n;
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r += d;
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}
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while (d >= 0.000010f * 10 || d <= -0.000010f * 10);
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return r;
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}
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#define round(a) (s16) (a+0.5)
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#endif
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