Re: stepping through a flat binary in qemu

[Michael Snyder <msnyder@vmware.com>]

fpga wrote:
> Hi. 
> I'm trying to step through a tiny real-to-pmode os in qemu using gdb.
> 
> I'm using 
>    nasm -f bin emakeimg.asm -o enth.fbin
> to assemble the thing and then pasting the 16bit flat binary to a floppy
> image
> i.e. no debugging symbols.
> 
> I've booted the os in qemu with 
> "qemu -s -S -fda boot.img -boot a" 
> & also without "-s" (use gstabs)
> 
> In another terminal I debug the same image and connect to qemu via
> "target remote localhost:1234".
> If I type "cont" the OS starts to execute.
> 
> If I try to step by typing "break" gdb complains about no symbols.
> Is it possible to step through this 16 bit bootloader code and into the OS
> proper with no symbols & if not what's the easiest way of putting symbols
> in.
> 
> I have a problem that if I try to assemble as elf, I have multiple [ORG
> statements in the code] which only bin files recognise.
> 
> Any help much appreciated.

Probably need to use stepi, since step depends on line symbols.