/*
    The IDA Pro Book - Listing 15-6
    Copyright (C) 2008 Chris Eagle <cseagle@gmail.com>

    This program is free software; you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by the Free
    Software Foundation; either version 2 of the License, or (at your option)
    any later version.

    This program is distributed in the hope that it will be useful, but WITHOUT
    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
    more details.

    You should have received a copy of the GNU General Public License along with
    this program; if not, write to the Free Software Foundation, Inc., 59 Temple
    Place, Suite 330, Boston, MA 02111-1307 USA

*/

#include <idc.idc>

static main() {
  auto addr, op, end, idx;
  auto func_flags, type, val, search;
  search = SEARCH_DOWN | SEARCH_NEXT;
  addr = GetFunctionAttr(ScreenEA(), FUNCATTR_START);
  func_flags = GetFunctionFlags(addr);
  if (func_flags & FUNC_FRAME) {  //Is this an ebp based frame?
    end = GetFunctionAttr(addr, FUNCATTR_END);
    for (; addr < end && addr != BADADDR; addr = FindCode(addr, search)) {
      type = GetOpType(addr, 0);
      if (type == 3) {  //Is this a register indirect operand?
        if (GetOperandValue(addr, 0) == 4) {   //Is the register esp?
          MakeComm(addr, "arg_0");  //[esp] equates to arg_0
        }
      }
      else if (type == 4) {  //Is this a register + displacement operand?
        idx = strstr(GetOpnd(addr, 0), "[esp"); //Is the register esp?
        if (idx != -1) {
          val = GetOperandValue(addr, 0);   //get the displacement
          MakeComm(addr, form("arg_%d", val));  //add a comment
        }
      }
    }
  }
}