AmigActive 13/AACD13.ISO/AACD/Programming/Atmel/Asm/src/math.c

C/C++ Source or Header | 2000-08-22 | 4.5 KB | 294 lines

/*******************************************************
* Maths routines for the Atmel cross assembler         *
* (c)1999 LJS                                          *
*                                                      *
* Takes an expression and evaluates it.                *
*******************************************************/

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

#include "errors.h"

#define MAXBUFFER 1024
extern int Error;

void InsertChar(char *S, char Ch);
int Evaluate(char *Exp);
int EvalBit(char *Bit);
int BracketOut(char *Str);
int CheckBrackets(char *Str);
int Math(char *Str);
void RemoveSpace(char *S);

int StrToInt(char *Str);     /*Converts hex,dec,bin*/

int Math(char *Str)
{
    int Result;
  char *Local, *Bit, Sign;

  if(strlen(Str)>=MAXBUFFER)
  {
    Error = MEM;
    return 0;
  }

  Local=(char*)malloc(MAXBUFFER);
  if(Local==NULL)
  {
    Error=MEM;
    return 0;
  }
  strcpy(Local,Str);            /*Take a local copy of the original expression*/
  if(CheckBrackets(Local)==0)
  {
    Bit = Local;
    while(*Bit)
    {
      Sign = *Bit;
      Bit++;
      if( (*Bit == '>') || (*Bit == '<') )  /*Splat >> & << to > & <*/
      {
        if(Sign == *Bit)
        {
          *Bit = ' ';    /*Change the second one to a space*/
        }
      }
    }
    RemoveSpace(Local);
      Result=BracketOut(Local);
        if(Result)
        {
          Result=Evaluate(Local);
         }
  }
  else
  {
    Error=BRACKETS;
  }
  free(Local);
 return Result;
}

int Evaluate(char *Exp)
{
    char *Work, *Double, *Temp;
    int Result;

  if(CheckBrackets(Exp))
  {
    return 0;
  }

  if( (strlen(Exp)+2) >=MAXBUFFER)
  {
    Error = MEM;
    return 0;
  }

    Work=(char*)malloc(MAXBUFFER);
    if(Work==NULL)
    {
        Error=MEM;
        return 0;
    }
    Double=(char*)malloc(MAXBUFFER);
    if(Double==NULL)
    {
        Error=MEM;
        free(Work);
        return 0;
    }

    Work[0]='(';
    Work[1]=0;
    strcat(Work,Exp);
    strcat(Work,")");
    Temp=Work;
    do
    {
        while( (*Temp!=')') && (*Temp) )
        {
            Temp++;
        }
        if(*Temp)
        {
            while(*Temp!='(')
            {
                Temp--;
            }
            Result=EvalBit(Temp);
            *Temp=0;
            sprintf(Double,"%s%d",Work,Result);
            while(*Temp!=')')
            {
                Temp++;
            }
            Temp++;
            strcat(Double,Temp);
            strcpy(Work,Double);
        }
        Temp=Work;
    }while(*Temp=='(');

    free(Work);
    free(Double);
    return Result;
}

int EvalBit(char *Bit)
{
    int Result=0, Os, Loop, Left, Right;
    char Part[2][8],Sign;

    for(Loop=0; Loop<2; Loop++)
    {
        Sign=*Bit;
        Bit++;
        Os=0;
        do
        {
            Part[Loop][Os]=*Bit;
            Os++;
            Bit++;                /*Gets -'s as well*/
        }while( (isxdigit(*Bit) || (*Bit=='$') || (*Bit=='%')) && (Os<8) );
        Part[Loop][Os]=0;
    }

    Left=StrToInt(Part[0]);
  if(Sign!=')')
  {
      Right=StrToInt(Part[1]);
  }

    switch(Sign)
    {
        case '+':Result=Left+Right;
                        break;
        case '-':Result=Left-Right;
                        break;
        case '*':Result=Left*Right;
                        break;
        case '/':if(Right)
                         {
                             Result=Left/Right;
                         }
                         else
                         {
                             Error=DIVZERO;
                         }
                        break;
        case '&':Result=Left&Right;
                        break;
        case '|':Result=Left|Right;
                        break;
        case '>':Result=Left>>Right;
                        break;
        case '<':Result=Left<<Right;
                        break;
        default:Result=Left;
                     break;
    }
 return Result;
}

void InsertChar(char *S, char Ch)
{
    char TempA, TempB;

  if( (strlen(S)+1) >= MAXBUFFER)
  {
    Error = TOOCOMPLEX;
    return;
  }

    TempA=*S;
    *S=Ch;
    while(*S)
    {
        S++;
        TempB=*S;
        *S=TempA;
        TempA=TempB;
    }
}

int BracketOut(char *Str)
{
    char *Order="/*+-&|<>";
    char *Temp,*StrPtr;
    int Bracket;

    while(*Order)
    {
        Temp=Str;
        while(*Temp)
        {
            if(*Temp==*Order)
            {
                StrPtr=Temp;
                Bracket=0;
                do
                {
                    StrPtr--;
                    if(*StrPtr==')')
                        Bracket++;
                    else if(*StrPtr=='(')
                        Bracket--;
                }while( ((Bracket) || isxdigit(*StrPtr) || (*StrPtr=='$') || (*StrPtr=='%')) && (StrPtr>Str) );
                if(StrPtr>Str)
                {
                    StrPtr++;
                }
        else if(StrPtr<Str)
        {
          return 1;
        }
                Temp++;
                InsertChar(StrPtr,'(');
        if(Error) return 0;
                Temp++;
                Bracket=0;
                if(*Temp)
                {
                    do
                    {
                        if(*Temp=='(')
                            Bracket++;
                        else if(*Temp==')')
                            Bracket--;

                        Temp++;
                    }while( ((Bracket) || isxdigit(*Temp)  || (*Temp=='$') || (*Temp=='%')) && (*Temp));
                }
                InsertChar(Temp,')');
        if(Error) return 0;
            }
            else
            {
                Temp++;
            }
        }
        Order++;
    }
    return 1;
}

int CheckBrackets(char *Str)
{
  int result=0;

  while(*Str)
  {
    if(*Str=='(')
      result++;
    if(*Str==')')
      result--;
    Str++;
  }
 return result;
}