sdk_math.h

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// fake MSL_C math for sdk specifically since it differs from game MSL_C math
 
extern inline float sqrtf(float x) {
    static const double _half=.5;
    static const double _three=3.0;
    volatile float y;
    if(x > 0.0f) {
        double guess = __frsqrte((double)x);   // returns an approximation to   
        guess = _half*guess*(_three - guess*guess*x);  // now have 12 sig bits
        guess = _half*guess*(_three - guess*guess*x);  // now have 24 sig bits
        guess = _half*guess*(_three - guess*guess*x);  // now have 32 sig bits
        y=(float)(x*guess);
        return y ;
    }
    return x ;
}   
 
extern inline float sqrt(float x) {
    static const double _half=.5;
    static const double _three=3.0;
    volatile float y;
    if(x > 0.0f) {
        double guess = __frsqrte((double)x);   // returns an approximation to   
        guess = _half*guess*(_three - guess*guess*x);  // now have 12 sig bits
        guess = _half*guess*(_three - guess*guess*x);  // now have 24 sig bits
        guess = _half*guess*(_three - guess*guess*x);  // now have 32 sig bits
        guess = _half*guess*(_three - guess*guess*x);  // now have 32 sig bits
 
        y=(float)(x*guess);
        return y ;
    }
    return x ;
}
 
extern inline float fabs(float x) {
#if __MIPS__
    return fabsf(x);
#else
    (*(int*)&x)&=0x7fffffff;
    return  x;
#endif
}
 
extern inline float fabsf(float x) {
    return __fabsf(x);
}
 
extern float cosf(float);
extern float sinf(float);
extern float tanf(float);
extern float acosf(float);
 
extern inline float cos(float x) {
    return cosf(x);
}
 
inline float floor(float x) {
    int i=(int)x;   
    float y=x-(float)i; 
 
    if(!y || x > 8388608.0f)
    return x ;               // x is already an int 
 
    if(x < 0) 
    return (float)--i;  
        // x < 0 -> int conversion of x above rounded toward zero(so decrement)                
    return (float)i;
}