Q re data breakpoints and variable size

[WSinc]

Hello -

I noticed when I debug a program,
when I set a DATA breakpointpoint, it
wants to know how many bytes are involved.

The defauly apparently is 4, since it does not seem to know how big the variable
is. How does that work?

Does it test all the bytes to see if ANY of them changed value?

Why can't I set it to the right value for Integer*8 or Real*16 variables?

[mecej4]

The seemingly odd restrictions are related to the architecture of the hardware debug registers of the i386 architecture. See, for example, this Web page .

Without hardware support, data breakpoints would be prohibitively cycle-consuming to implement.

[WSinc]

So, is there a way to debuf integer*1 or integer*2, or even real*8 variables?

It isn;t clear that a given PC has an 80386 CPU. Does that web page also apply to OTHER cpus?

I will print it out and have a look.

[Steven_L_Intel1]

You are certainly not using an 80386 CPU from the 1980s. But the fact remains that data breakpoints under 32-bit Windows are limited to 32-bits (four bytes) or less. Yes, you can break on two and one-byte values.

For a 64-bit application, you can set a data breakpoint on a 64-bit (8-byte) value.