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Re: how does GDB set breakpoint to MPC860.
- To: Tony Ko <nhko at gctsemi dot com>
- Subject: Re: [ECOS] how does GDB set breakpoint to MPC860.
- From: Jonathan Larmour <jlarmour at redhat dot com>
- Date: Mon, 18 Jun 2001 14:59:02 +0100
- Cc: ecos-discuss at sources dot redhat dot com
- Organization: Red Hat UK Ltd.
- References: <9860C773D04D834D83FD6FAD00A61E9311B6F8@gctsemi.gctsemi.com>
Tony Ko wrote:
>
> hi.
> I'm curious about HOW GDB sets breakpoint to MPC860 when source-level-
> debugging.
For eCos it just uses software breakpoints. I don't know off-hand whether
there's a special breakpoint instruction, or if it is an illegal
instruction; but in either case the instruction at the breakpoint address
is replaced with the breakpoint instruction, which causes a trap which
causes the stub to be entered. The original contents of the insn at the
breakpoint address are restored when continuing from the breakpoint.
> ( I mean what registers are used and something like that)
> and more, what's mean by single-step trace?
I don't think I've heard of the specific term "single-step trace", although
single-stepping is obvious. What's the context?
Jifl
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