title: GDB complains No Source Available
body: <p>I'm running on Ubuntu 12.10 64bit.</p>
  
  <p>I am trying to debug a simple assembly program in GDB. However GDB's gui mode (-tui) seems unable to find the source code of my assembly file. I've rebuilt the project in the currently directory and searched google to no avail, please help me out here.</p>
  
  <p>My commands:</p>
  
  <pre><code>nasm -f elf64 -g -F dwarf hello.asm
  
  gcc -g hello.o -o hello
  
  gdb -tui hello
  </code></pre>
  
  <p>Debug information seems to be loaded, I can set a breakpoint at main() but the top half the screen still says '<strong>[ No Source Available ]</strong>'.</p>
  
  <p>Here is hello.asm if you're interested:</p>
  
  <pre><code>;  hello.asm  a first program for nasm for Linux, Intel, gcc
  ;
  ; assemble: nasm -f elf -l hello.lst  hello.asm
  ; link:     gcc -o hello  hello.o
  ; run:          hello 
  ; output is:    Hello World 
  
      SECTION .data       ; data section
  msg:    db "Hello World",10 ; the string to print, 10=cr
  len:    equ $-msg       ; "$" means "here"
                  ; len is a value, not an address
  
      SECTION .text       ; code section
          global main     ; make label available to linker 
  main:               ; standard  gcc  entry point
  
      mov edx,len     ; arg3, length of string to print
      mov ecx,msg     ; arg2, pointer to string
      mov ebx,1       ; arg1, where to write, screen
      mov eax,4       ; write command to int 80 hex
      int 0x80        ; interrupt 80 hex, call kernel
  
      mov ebx,0       ; exit code, 0=normal
      mov eax,1       ; exit command to kernel
      int 0x80        ; interrupt 80 hex, call kernel
  </code></pre>