Assembler: crash at function call.

category: general [glöplog]

Hello.

I've recently stared learning 80x86 assembly language with this tutorial. And I have a little problem with function calls. Everytime I do a function call my program crashes. And the strange thing is that the author's asm examples crashes as well.

I'm using NASM and MinGW's gcc.

What I do is:
driver.c

Code:


int asm_main();

int main(int argc, char *argv[])
{
  int status = asm_main();
  return status;
}

test.asm

Code:


segment .data
  msg1   db "printf() test!",0
  format db "%s",0

segment .bss

segment .text
  global _asm_main
  extern _printf
_asm_main:
  enter 0,0
  pusha

  push dword msg1
  push dword format
  call _printf
  pop ecx
  pop ecx

  popa
  mov eax,0
  leave
  ret

And the build commands are:

Code:


C:\asm>gcc -c driver.c
C:\asm>nasm -f coff test.asm
C:\asm>gcc -o test.exe driver.o test.o

So... what's wrong with it?
Thanks for any help.

added on the 2006-09-30 20:55:02 by masterm

Code:


gcc -c driver.c
nasm -f win32 test.asm
gcc -o test.exe driver.o test.obj

added on the 2006-10-01 02:26:41 by hitchhikr

Thanks a lot! :) I didn't notice I was using wrong object format.

added on the 2006-10-01 11:32:00 by masterm

microsoft says they're using COFF format, but in reality it's not COFF format. Got me once badly when I was porting the System16 emulator from DOS to Windows. Had to write a tool to convert assembler sources from GNU syntax to Nasm/Intel syntax.
The mean thing about this incompatibility is that no part of the toolchain (even MSVC) complains, and then when running the code the relocs are totally messed up...
cheers

added on the 2006-10-01 14:27:03 by bartman

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Assembler: crash at function call.

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