#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>



//ビット列をただそれを表す数に直す（符号ビットなし）
unsigned int my_btoi(char *str){
  unsigned int x=0 ;
  int i, j, k;
  for(i=0; i<=31; i++){
    if(str[i]=='1'){
      x+=pow(2, (31-i));
    }
  }
  return x;
}

//整数をただのビット列に直す（符号ビットなし）
void  my_itob(unsigned int x, char* tmp){
  int i;
  char str[33];
  for(i=0; i<=31; i++){
    if(x>=pow(2, (31-i))){
      str[i]='1';
      x-=pow(2, (31-i));
    }else{
      str[i]='0';
    }
    
  }
  
  strcpy(tmp, str);
}



//ビット列を整数に直す（1の補数で）
unsigned int btoi32(char* str){
  int i , j, k ;
  unsigned  int x=0 ;
  if(str[0]=='0'){    //正の数
    for(i=1; i<32; i++){
      if(str[i]=='1')
	x+=pow(2,(31-i));
    }
  }else if(str[0]=='1'){ //負の数
    for(i=1; i<32; i++){
      if(str[i]=='0')
	x+=pow(2, (31-i));
    }
    x+=1;
    x*=(-1);
  }
  return x;
}

//整数をビット列に直す（1の補数で)
void itob(int a, char *str1){
  char str[33];
  int i, k, j;
  str[32]='\0';
  if(a>=0){          //正の数
    str[0]='0';
    for(i=1; i<32; i++){
      if(a>=pow(2, (31-i))){
	a-=pow(2, (31-i));
	str[i]='1';
      }else{
	str[i]='0';
      }
    }
  }else if(a<0){     //負の数
    str[0]='1';
    a=(-1)*a -1;
    for(i=1; i<32; i++){
      if(a>=pow(2,(31-i))){
	a-=pow(2,(31-i));
	str[i]='0';
      }else{
	str[i]='1';
      }
    }
  }
  strcpy(str1, str);
}

//32ビット列を浮動小数点にする
float btod (char* str){
  int exp=0; 
  float a=1.0;

  int i, k, j;
  int sign;
  j=0;
  if(str[0]== '0'){
    //   puts("sei");
    sign=0;
  }
  if(str[0]== '1'){
    //  puts("fu");
    sign=1;
  }

  for(i=1; i<=8; i++){
    if(str[i]=='1'){
      exp+=pow(2,8-i);
    }else if(str[i]=='0'){
      j+=1;
    }
  }
  exp-=127;
  a =pow(2,exp);
  for(i=9; i<32; i++){
    if(str[i]=='1'){
      a += pow(2, ((-1)*i+8+exp));
    }
  }
  if(j==8)
    return 0;
  if(sign==0)
    return a;
  if(sign==1)
    return (-1)*a;
}


  


//浮動小数点をビット列にして引数の文字列に渡す
void dtob(float a, char *str ){
  
  char tmp_str[33];
  int exp=0;  //指数部　ー127済み
  int i, j, k; 
  float  abs; //引数の絶対値

  tmp_str[32] = '\0';
  
  if(a>=0){
    abs=a;
    tmp_str[0]= '0';
  }else{
    abs= a* (-1);
    tmp_str[0]= '1' ;
  }
 // printf("a: %.f\n", a);
  
  
  if(abs >=2){
    while(abs >=2){
      exp+=1;
      abs /=2;
     
    }
    exp+=127;
  }else if(abs == 0){
    exp=0;           //0のときは指数部も0
  }else if(abs <1 ){
    while(abs<1){  //仮数部の最初のビットが1となるように調整
      exp -=1;
      abs *=2;
    }
    exp+=127;
  }else if(abs>=1 && abs<2){
    exp = 127;
  }
 
  for(i=1; i<=8; i++){
    if(exp>= pow(2,8-i)){
      exp-=pow(2, 8-i);
      tmp_str[i]= '1';
    }else{
      tmp_str[i]= '0';
    }
  }
  
  
  
  abs -=1;  //隠れている最初のビット1を引く

  
  for(i=0; i<23; i++){
    if(abs >= pow(2, (-i-1))){
      tmp_str[i+9]= '1';
      abs-= pow(2, (-i-1));
    }else{
      tmp_str[i+9]= '0';
    }
  }
  
  strcpy(str, tmp_str);

}

unsigned int fpu_fadd(unsigned int in1, unsigned int in2){
  char c1[33];
  char c2[33];
  char c3[33];
  
  float a, b, c;
  unsigned int x;
  
  my_itob(in1, c1);
  my_itob(in2, c2);
  
  a=btod(c1);
  b=btod(c2);
  c=a+b;
  dtob(c, c3);
  x = my_btoi(c3);
  return x;
}


unsigned int fpu_fsub(unsigned int in1, unsigned int in2){
  char c1[33];
  char c2[33];
  char c3[33];
  
  float a, b, c;
  unsigned int x;
  
  my_itob(in1, c1);
  my_itob(in2, c2);
  
  a=btod(c1);
  b=btod(c2);
  c=a-b;
  dtob(c, c3);
  x = my_btoi(c3);
  return x;
}




unsigned int fpu_fmul(unsigned int in1, unsigned int in2){
  char c1[33];
  char c2[33];
  char c3[33];
  
  float a, b, c;
  unsigned int x;
  
  my_itob(in1, c1);
  my_itob(in2, c2);
  
  a=btod(c1);
  b=btod(c2);
  c=a*b;
  dtob(c, c3);
  x = my_btoi(c3);
  return x;
}


unsigned int fpu_inv(unsigned int in1){
  char c1[33];
  char c2[33];
  
  float a, b;
  unsigned int x;
  
  my_itob(in1, c1);
  a=btod(c1);
  if(a==0){
    printf("error: input 0 to fpu_inv\n");
    return 0;
  }
  
  b=1/a;
  dtob(b, c2);
  x = my_btoi(c2);
  return x;
  
}



unsigned int fpu_finvsqrt(unsigned int  in1){

  char c1[33];
  char c2[33];
  
  float a, b;
  unsigned int x;
  
  my_itob(in1, c1);
  a=btod(c1);
  if(a<=0){
    printf("nan\n");
    return 0;
  }
  b= 1/sqrt(a);
  dtob(b, c2);
  x = my_btoi(c2);
  return x;

}

unsigned int  fpu_ftoi(unsigned int in1){
  unsigned int x;
  char c1[33];
  char c2[33];
  float a;
  my_itob(in1, c1);
  a=btod(c1);
  if(a>=0){
    x=(int)(0.5+a);
  }else{
    x=(int)(a-0.5);
  }
  return x;
}


unsigned int  fpu_itof(unsigned int in1){
  float a;
  unsigned int x;
  char c1[33];
  a=(float)in1;
  dtob(a, c1);
  x=my_btoi(c1);
  return x;
}


unsigned int  fpu_fless(unsigned int in1, unsigned int in2){

  char c1[33];
  char c2[33];
  char sub1[32];
  char sub2[32];
  
  float a, b;
  unsigned int x;
  
  int f1,f2,f3,f4; //flag
  my_itob(in1, c1);
  my_itob(in2, c2);
  printf("c1---%s,  c2---%s\n", c1, c2);
  strncpy(sub1,c1,9);
  strncpy(sub2,c2,9);
 
  sub1[9]='\0';
  sub2[9]='\0';
  
  printf("sub1-%s\n", sub1);
  printf("sub2-%s\n", sub2);
  
  f1=strcmp(sub1, "000000000");
  f2=strcmp(sub1, "100000000");
  f3=strcmp(sub2, "000000000");
  f4=strcmp(sub2, "100000000");
  
  printf("f1--%d, f2--%d, f3--%d, f4--%d\n", f1,f2,f3,f4);
  
  if((f1==0)&&(f3==0)){ 
  return 0;
  }
  
  if((f2==0)&&(f3==0)){
  return -1;
  }
  
  if((f1==0)&&(f4==0)){
  return 0;
  }
  
  if((f2==0)&&(f4==0)){
  return 0;
  }
   
  
  a=btod(c1);
  b=btod(c2);
  
  if(a<b){
    return -1;                  //  ??? 
  }else{
    return 0;
  }
}






//for test

/*
int main(){
  float a, b, c, d, e, f, g, h;
  char c1[33];
  char c2[33];
  char c3[33];
  char c4[33];
  char c5[33];
  char c6[33];
  char c7[33];
  char c8[33];
  char c9[33];


  unsigned int n1, n2, n3, n4, n5, n6, n7, n8, n9, n10;

  puts("f1:");
  scanf("%f", &a);
  puts("f2:");
  scanf("%f", &b);
  dtob(a, c1); //float to bit array
  dtob(b, c2);
  n1=my_btoi(c1);//bit array to unsigned int 
  n2=my_btoi(c2);
  n3=fpu_fadd(n1,n2); //operation
  n4=fpu_fsub(n1,n2); 
  n5=fpu_fmul(n1,n2); 
  n6=fpu_inv(n1);
  n7=fpu_finvsqrt(n1);
  n8=fpu_ftoi(n1);
  n9=fpu_itof(100);
  n10=fpu_fless(n1, n2);


  
  my_itob(n3,c3);
  c=btod(c3);
  printf("fadd: %f\n", c);
  
  my_itob(n4,c4);
  d=btod(c4);
  printf("fsub: %f\n", d);
  
  my_itob(n5,c5);
  e=btod(c5);
  printf("fmul: %f\n", e);
  
  my_itob(n6,c6);
  f=btod(c6);
  printf("fpu_inv of %f: %f\n", a, f);
  
 
  my_itob(n7,c7);
  g=btod(c7);
  printf("fpu_finvsqrt of %f: %f\n",a, g);

  printf("fpu_ftoi: %d\n", n8);

  my_itob(n9,c9);
  h=btod(c9);
  printf("fpu_itof of 100: %f\n", h);
  
  printf("fpu_fless: %d\n", n10);
  
 
   
  return 0;
}

*/