CoolPotOS/apps/libs/math.c

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2024-09-01 14:56:38 +08:00
#include "../include/math.h"
static unsigned long long rand_seed = 1 ;
static unsigned short max_bit = 32 ;
static unsigned short randlevel = 1 ;
const unsigned long long rand(){
unsigned short i = 0;
while(i < randlevel)
rand_seed = rand_seed * 1103515245 + 12345 , rand_seed <<= max_bit , i ++ ;
return (const unsigned long long)(rand_seed >>= max_bit) ;
}
void srand(unsigned long long seed){
rand_seed = seed ;
}
void smax(unsigned short max_b){
max_b = (sizeof(unsigned long long) * 8) - (max_b % (sizeof(unsigned long long) * 8)) ;
max_bit = (max_b == 0) ? (sizeof(unsigned long long) * 8 / 2) : (max_b) ;
}
void srandlevel(unsigned short randlevel_){
if(randlevel_ != 0)
randlevel = randlevel_ ;
}
int32_t abs(int32_t x){
return (x < 0) ? (-x) : (x) ;
}
double pow(double a,long long b){
char t = 0 ;
if(b < 0)b = -b , t = 1 ;
double ans = 1 ;
while(b){
if(b & 1)ans *= a ;
a *= a ;
b >>= 1 ;
}
if(t)return (1.0 / ans) ;
else return ans ;
}
//快速整数平方
unsigned long long ull_pow(unsigned long long a,unsigned long long b){
unsigned long long ans = 1 ;
while(b){
if(b & 1)ans *= a ;
a *= a ;
b >>= 1 ;
}
return ans ;
}
double sqrt(double x){
if(x == 0)return 0.0 ;
double xk = 1.0,xk1 = 0.0 ;
while(xk != xk1)xk1 = xk , xk = (xk + x / xk) / 2.0 ;
return xk ;
}
//快速求算数平方根(速度快,精度低)
float q_sqrt(float number){
long i ;
float x,y ;
const float f = 1.5F ;
x = number * 0.5F ;
y = number ;
i = *(long*)(&y) ;
i = 0x5f3759df - (i >> 1) ;
y = *(float*)(&i) ;
y = y * (f - (x * y * y)) ;
y = y * (f - (x * y * y)) ;
return number * y ;
}