Re: [Qemu-devel] Breaking on start of MBR

[Johannes Schindelin]

Hi,

On Tue, 10 Jan 2006, Jan Rupar wrote:

> I'm trying to use QEMU step through some MBR assembly code by using
> gdb remotely, and I can't figure out where to set the breakpoint.  I
> know that on a native PC the MBR code gets relocated to 0x7c00, but
> that didn't work when running through QEMU.  I'm using the -S switch
> to stop the emulator at the beginning.  How would you guys do it?

I'd do the following: start QEmu itself in gdb, breakpoint at raw_read(), 
let QEmu run until the sector_num == 0, and then set the current env's 
singlestep_enabled member to 1.

You might have to recompile the code after adjusting it a bit (for example 
to get the current env, or to go into an if() clause when sector_num == 
0).

Hth,
Dscho