Re: [discuss] semantics, "replay debugging" vs. "reverse debugging"

Daniel Jacobowitz
2008-10-22T13:37:58Z

On Wed, Oct 22, 2008 at 11:25:17AM +0800, teawater wrote:
> I think your not clear my idea.
>
> > I think maybe some instruction can do it.
> > Such as add instruction. When it forward execute, it add some number
> > to a value of register. When it reverse, it can sub this number from
> > the value of register. It can reverse without record.
>
> Maybe you can read this part again.
>
> And what is the status of program? Most of time, it's just the values
> of registers and memory. Do not think anything that complex.

Jakob is right. For instance, if the add instruction sets an overflow
flag in the status register, you can not figure out what the previous
version of the overflow flag was after the instruction.

--
Daniel Jacobowitz
CodeSourcery