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Transfer system

Transfer system

Transfer system

Im new to assembly and i m currently trying to learn.I ve been trying to develop a transfer system between 2 computers using a null modem cable. I ve managed to code my transmitter but i can't get around the reverse proccess and code the receiver.Could someone help me with it?
Here is my transmitter:


#include <stdio.h>

int main (void) {

 //Define Variables
  char Textfile[] = "C:\\text.txt";   //File that holds the data to transmit
  char Comport[] ="COM2";                   //Define Serial Port

  FILE * readfile;
  FILE * writecom;

  char error[] = "Unable to open File/Comport\n\n"; //TERMINATION with an error message
  char chartosend;
  char readaccess[] ="r";
  char writeaccess[] ="wt";

  _asm {

//check if the port can be accessed
      lea eax,writeaccess   //check acess and move it to the stack
      push eax
      lea eax,Comport       //check port and move it to the stack
      push eax

      call fopen
      add esp,8   //Clean the stack

      cmp eax, 0
      mov writecom, eax
      je TERMINATION //If it doesn't writecom then run TERMINATION for handling errors

//check if textfile is accessible
      lea eax,readaccess  //check for readaccess for the textfile and move it to the stack
      push eax
      lea eax, Textfile     //check for textfile and move it to the stack
      push eax

      call fopen
      add esp, 8 //Clean the stack

      cmp eax, 0
      mov readfile, eax
      je TERMINATION    //If it doesn't open readfile then run TERMINATION for handling errors

//IF no more data can be read from a data source get each character from the file
     mov eax, readfile
     push eax

     call fgetc
     add esp, 4
//check if EOF has been reached
     cmp al, EOF

     mov chartosend, al

     push eax
     add esp, 4
//write characters to comport
     mov eax, writecom
     push eax
     mov al, chartosend
     push eax
     call fputc
     add esp, 8


//Add closing value to the end of the string
     mov eax, writecom
     push eax

     mov al, 80h  //The receiver needs to know the EOF so closing value is 80h
     push eax

     call fputc
     add esp,8

//Start closing
     mov eax, readfile  //readfile
     push eax

     call fclose
     add esp, 4

     mov eax, writecom
     push eax

     call fclose
     add esp, 4

     jmp END

     lea eax, error
     push eax

     call printf
     add esp, 4

     } //_asm

    return 0;
    } //void
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