#include "stdafx.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <time.h>

unsigned int *arrBase;
unsigned int *arrCac;
unsigned int *arrResult;

unsigned int DecNum=1000;
unsigned int NUM;
unsigned int StartPos;
unsigned int StartPos4;
void initArr(unsigned int* arr)
{
 _asm{
  mov ecx, NUM
  mov ebx, arr
_init: 
  mov dword ptr [ebx],0
  add ebx,4
  loop _init
 }
}

 


void addArr(unsigned int* arr,unsigned int* arr2)
{
 __asm{
  mov ecx, NUM
  mov esi, arr
  mov edi, arr2
  mov eax, ecx
  shl eax, 2
  add esi, eax
  add edi, eax
  clc
_add:
  sub esi, 4
  sub edi, 4
  mov eax, [edi]
  adc [esi],eax
  loop _add
 }

}

void subArr(unsigned int* arr,unsigned int* arr2)
{
 
 _asm {
  mov ecx, NUM
  dec ecx
  mov esi, arr
  mov edi, arr2
  clc
_sub:
  mov eax, [edi+ecx*4]
  sbb [esi+ecx*4],eax
  loop _sub
 }
}

void mulArr(unsigned int* arr,unsigned int num)
{
 _asm{
  mov ecx,NUM

  mov ebx,ecx
  shl ebx,2
  add ebx,arr
  xor edx,edx
  mov edi,num
  xor esi,esi
_mul:
  sub ebx,4
  mov eax,[ebx]
  mul edi
  add eax,esi
  mov [ebx],eax
  adc edx,0
  mov esi,edx
  loop _mul

 }
}

void divArr(unsigned int *arr,unsigned int num)
{
 __asm{
  mov ebx,arr
  mov ecx,NUM
  xor edx,edx
_div: mov eax,[ebx]
  div num
  mov [ebx], eax
  add ebx,  4
  loop _div
 }
}


/*
caculate arctan(1/num), and store the result to arr
*/
void arctanX(unsigned int num)
{
 
 unsigned int dd;
 unsigned int remain=0;
 unsigned int loopN;
 dd=(long)num*num;
 loopN=(int)(32*NUM*log(2)/log(5));
 initArr(arrBase);
 initArr(arrCac);
 arrBase[0]=1;
 divArr(arrBase,num);
 StartPos=1;
 _asm mov ebx,1

forloopN:
 _asm mov eax, StartPos
 _asm shl eax, 2
 _asm mov StartPos4,eax
 _asm mov edi, arrCac
 _asm add edi, StartPos4
 _asm mov esi, arrBase
 _asm add esi, StartPos4
 _asm mov ecx, NUM
 _asm sub ecx, StartPos
 _asm xor edx, edx
 
 
 _asm test ebx,2
 _asm jnz cond2
 cond1:
  fori1:
   
      _asm mov eax, [esi]
   _asm div ebx
addCac:  
   _asm add [edi], eax
   _asm jnc fori11
   _asm push edi
addCarry: _asm sub edi, 4
   _asm add dword ptr [edi], 1
   _asm jc addCarry
   _asm pop edi
fori11:  
   _asm add edi, 4
   _asm add esi, 4
   _asm loop fori1
   
   _asm jmp divarrBase

 cond2:   
  fori2:
   _asm mov eax, [esi]
   _asm div ebx
subCac:
   _asm sub [edi], eax
   _asm jnc fori22
   _asm push edi
subCarry:
   _asm sub edi, 4
   _asm sub dword ptr [edi],1
   _asm jc subCarry
   _asm pop edi
  fori22:   
   _asm add esi, 4
   _asm add edi, 4
   _asm loop fori2
     

 divarrBase:
  _asm xor eax, eax
  _asm xor edx, edx
  _asm mov esi, dd
  
  _asm mov edi, arrBase
  _asm mov ecx, NUM


  forBase:
  _asm mov eax,[edi]
  _asm div esi
  _asm mov [edi], eax
  _asm add  edi, 4
  _asm loop forBase

_asm inc ebx
_asm inc ebx
_asm mov esi, arrBase
_asm mov eax, StartPos
_asm shl eax, 2
_asm add esi, eax
_asm cmp dword ptr [esi],0
_asm jnz forloopN
_asm inc StartPos
_asm mov eax,StartPos
_asm cmp eax, NUM
_asm jb forloopN
 
}

void pArr(unsigned int arr[])
{ 
 printf("%d.\n",arr[0]);
 for(unsigned int i=1;i<NUM;i++){
  arr[0]=0;
  mulArr(arr,100000);
  printf("%05ld",arr[0]);
  if(i%20==0) printf("\n");
 }
}

 unsigned int main()
 {
  unsigned int x;
  unsigned int i;
  unsigned int j;
  unsigned int buf[10];
  unsigned int tmp;
  FILE* fp;
  time_t timerStart, timerEnd;
  printf("-----caculating pi--------\n");
  printf("input nums of pi:");
  scanf("%d",&DecNum);
  NUM= (int)(DecNum / log10(2) / 32) + 4;
  arrBase=(unsigned int*)calloc(NUM,4);
  arrCac=(unsigned int*)calloc(NUM,4);
  arrResult=(unsigned int*)calloc(NUM,4);

  if(arrBase==NULL || arrCac==NULL || arrResult==NULL)
  {
   printf("\nerror alloc memory!");
   return 9;
  }
  time(&timerStart);
  printf("working... ...");
  x=5;
  initArr(arrResult);
  arctanX(x);
    mulArr(arrCac,16);
  addArr(arrResult,arrCac);
  
  x=239;
  arctanX(x);
  mulArr(arrCac,4);
  subArr(arrResult,arrCac);
  time(&timerEnd);
  printf(" ok,time used: %ld\n",timerEnd-timerStart);
  fp=fopen("pi.txt","w+");
  if(fp==NULL){
   printf("error! create file");
   return 2;
  }

  else{
   fprintf(fp,"%d.\n",arrResult[0]);
   for(i=1;i<=DecNum/5;i++){
    arrResult[0]=0;
    mulArr(arrResult,100000);
    fprintf(fp,"%05d",arrResult[0]);
    if(i%20==0) fprintf(fp,"\n");
    
    
   }
   fclose(fp);

  }
  return 0;
 }