How to set a memory breakpoint in vc7?

[Guest]

My purpose is to know which code reads value from a certain address. So I want to set a memory breakpoint and when cpu reads from the address, the breakpoint will be hit. But in the "Data breakpoint" in vc7, there are only two kinds of condition: "is true" and "has changed". How can I do?

 

[roman ziak]

My purpose is to know which code reads value from a certain address. So I want to set a memory breakpoint and when cpu reads from the address, the breakpoint will be hit. But in the "Data breakpoint" in vc7, there are only two kinds of condition: "is true" and "has changed". How can I do?

I would suggest to use no condition at all.

However, I did not know about data breakpoints and I have a question to
somebody who knows about how is this done on Intel processors.

Roman

 

[Jan Bares]

Hi,

you need hardware breakpoints, but VC doesn't use them. With little effort
you can use them from ;you code, they impose no overhead on code execution.
See here http://www.morearty.com/code/breakpoint/.

Regards, Jan

My purpose is to know which code reads value from a certain address. So I

want to set a memory breakpoint and when cpu reads from the address, the
breakpoint will be hit. But in the "Data breakpoint" in vc7, there are only
two kinds of condition: "is true" and "has changed". How can I do?

 

[Ronald Laeremans [MSFT]]

Actually the VS debugger's data breakpoints are done as hardware
breakpoints. Their used to be emulated data breakpoints as well but we
removed them altogether.

Ronald Laeremans
Visual C++ team

 

[Guest]

Yes, I need hardware breakpoint. In other debuger, like windbg, gdb, it's very easy to set a hardware breakpoint. It's strange why vc can't do it distinctly.

So how can I set a "read" hardware breakpoint????

 

[Ronald Laeremans [MSFT]]

The VS debugger only supports HW write breakpoints, not read breakpoints. I
entered a suggestion in the bug database that we support read breakpoints as
well.

Ronald