mirror of
https://github.com/ACreTeam/ac-decomp
synced 2026-05-23 06:34:18 -04:00
Roman Sandu
88 lines
2.3 KiB
C
88 lines
2.3 KiB
C
#ifndef W_MATH_H
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#define W_MATH_H
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#include "MSL_C/MSL_Common/float.h"
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#ifndef BUGFIXES
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#define SQRTF_LINKAGE extern
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#else
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// making the function static instead of extern resolves the bug
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#define SQRTF_LINKAGE static
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#endif
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/**
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* Float square root implementation.
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*
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* NOTE: this function causes a bug in the Metrowerks C Compiler from GC MW 1.3.X
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* to be exhibited. Weak extern inlined functions that contain an initialized
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* static variable turn off data pooling for the translation unit which they are
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* included in. As w_math.h seems to be included in a top-level header that
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* the AC devs used, every translation unit in foresta.rel includes sqrtf.
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* The effect is that the .rodata section has pooling entirely disabled.
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*/
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SQRTF_LINKAGE inline float sqrtf(float x) {
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static const double _half = .5;
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static const double _three = 3.0;
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volatile float y;
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if (x > 0.0f) {
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double guess = __frsqrte((double)x); // returns an approximation to
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guess = _half * guess * (_three - guess * guess * x); // now have 12 sig bits
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guess = _half * guess * (_three - guess * guess * x); // now have 24 sig bits
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guess = _half * guess * (_three - guess * guess * x); // now have 32 sig bits
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y = (float)(x * guess);
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return y;
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}
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return x;
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}
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#ifdef SQRTF_LINKAGE
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#undef SQRTF_LINKAGE
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#endif
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// Dirty hack to avoid the current header mess
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#ifndef FABS_DECLARED
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#define FABS_DECLARED
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extern inline double fabs(double x) {
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return __fabs(x);
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}
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#endif
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inline float fabsf(float x) {
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return (float)fabs((double)x);
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}
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#define INFINITY (*(float*)__float_huge)
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#define NAN (*(float*)__float_nan)
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#define HUGE_VALF (*(float*)__float_huge)
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extern inline double sqrt(double x) {
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if (x > 0.0) {
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double guess = __frsqrte(x);
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guess = .5 * guess * (3.0 - guess * guess * x);
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guess = .5 * guess * (3.0 - guess * guess * x);
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guess = .5 * guess * (3.0 - guess * guess * x);
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guess = .5 * guess * (3.0 - guess * guess * x);
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return x * guess;
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} else if (x == 0.0f) {
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return 0.0;
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} else if (x) {
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return NAN;
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}
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return INFINITY;
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}
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#ifdef __cplusplus
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extern "C" {
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#endif
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// double atan2(double, double);
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// double acos(float);
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#ifdef __cplusplus
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}
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#endif
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#endif
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