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#include <stdio.h>
#define Qx 4
#define Qy 4
#define Qz 4
/*in the fixed example,the default value of Q is 4.*/
/*The range of date is [-2048,2047.9375]*/
int fixed_add(int x,int y);
int fixed_sub(int x,int y);
int fixed_mul(int x,int y);
int fixed_sub(int x,int y);
double float_add(double x,double y);
double float_sub(double x,double y);
double float_mul(double x,double y);
double float_div(double x,double y);
int float_fixed(double x);
double fixed_float(int x);
/*********************************************************************/
void main(){
int fix_add,fix_sub,fix_mul,fix_div,fix_n;
double floa_add,floa_sub,floa_mul,floa_div,float_n;
for(;;) {
fix_add=fixed_add(1556,40);
fix_sub=fixed_sub(334,222);
fix_mul=fixed_mul(188,188);
fix_div=fixed_div(188,18);
floa_add=float_add(2.5e3,1.2e3);
floa_sub=float_sub(2.0e2,3.0e2);
floa_mul=float_mul(2.0e2,3.0e2);
floa_div=float_div(2.0e4,2.0e2);
fix_n=float_fixed(9.735e1);
float_n=fixed_float(1557);
}
}
/*******************************************************************************/
int fixed_add(int x,int y){
long temp;
int z;
temp=y<<(Qx-Qy);
temp+=x;
if (Qx>=Qz) {
z=temp>>(Qx-Qz);
}
else {
z=temp<<(Qz-Qx);
}
return z;
}
int fixed_sub(int x,int y){
long temp;
int z;
temp=y<<(Qx-Qy);
temp=x-temp;
if (Qx>=Qz) {
z=temp>>(Qx-Qz);
}
else {
z=temp<<(Qz-Qx);
}
return z;
}
int fixed_mul(int x,int y){
long temp;
int z;
temp=(long)x;
z=(temp*y)>>(Qx+Qy-Qz);
return z;
}
int fixed_div(int x,int y){
long temp;
int z;
temp=(long)x;
z=(temp<<(Qz-Qx+Qy))/y;
return z;
}
double float_add(double x,double y){
double z;
z=x;
z+=y;
return z;
}
double float_sub(double x,double y){
double z;
z=x;
z-=y;
return z;
}
double float_mul(double x,double y){
double z;
z=x;
z*=y;
return z;
}
double float_div(double x,double y){
double z;
z=x;
z/=y;
return z;
}
int float_fixed(double x){
int i;
int n;
for(i=0;i<Qx;i++) {
x*=2;
}
n=(int)x;
return n;
}
double fixed_float(int x){
int i;
double n;
n=x;
for(i=0;i<Qx;i++) {
n/=2;
}
return n;
}
问题1:/*The range of date is [-2048,2047.9375]*/ 数据范围为什么是-2048到2047.9375
问题二:定点加法运算为什么要移位移来移去的?不是一句话直接x+y搞定么?还有那个QX,QY,QZ代表什么东东
问题三:乘法运算为什么最后还要移位? |
阿莫论坛20周年了!感谢大家的支持与爱护!!
一只鸟敢站在脆弱的枝条上歇脚,它依仗的不是枝条不会断,而是自己有翅膀,会飞。
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