Hi Bill.

19-May-04 23:27:01, Bill Birrell wrote to Neil Heller


 BB> Assuming that you are talking about xxx86 CPU, you can insert the
 BB> breakpoint into the actual (or simulated) address as a byte
 BB> operand. OXC3 seems to come to mind (that is a one-byte RET
 BB> instruction). The clever bit is what you do to restore the
 BB> original code when you reach the breakpoint. The ret instruction
 BB> fills the bill because it pops the return address off the stack
 BB> and allows you to implement a standard procedure at that point

Data breakpoints are activated when an operation accesse a data location.

It's like setting a breakpoint on a variable "x" and every the
variable "x"
is used (or optionaly only when modified) the execution halts in the debugger.

Extremely hard to do in software without interpreting the entire program.

 -=> Bye <=-

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