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I need to put some ?CO? and ?XD? segments at a physical address which is different than the logical one (used in the program). I don't know how to.
I have succeeded doing this only with executable segments with this syntax: ?PR?*?SEG(logical_address)[!physical_address]
Can anyone help me?
"I need to put some ?CO? and ?XD? segments at a physical address which is different than the logical one (used in the program). I don't know how to."
Unless the 8051 derivative you are using has a MMU, I really don't know what you are talking about.
Could you please explain the difference between logical and physical addresses?
Indeed it has a MMU.
Any clue?
Please tell us what the exact chip you're using is, then maybe we can have a look at the data sheet and see what's what.
"Indeed it has a MMU. Any clue?"
I see, this is a contest. How many tries we have, and what are the prizes?
I am very interested since i already tried to implement the MMU of a Philips 8-bit micro-controller and i've got a lot of problem : - i cannot put ?CO? segments with virtual addresses - i cannot debug (put some breakpoints) directly inside C source files but only in dissasembly mode (not very easy) ...
Thanks, /tony
Would you please tell which chip are you using?
See here for more information about the usage of the SEGMENT directive.
the chip is a Philips SmartMx (8-bit microcontroller).
Any idea to help me?
I've contacted Philips requesting a datasheet for this controller, but haven't heard back. I can't seem to find anything on their website aside from their "short form specification." If you have the datasheet for your chip, please forward it to me at jdaniel@NOSPAM.ieee.org. (remove the NOSPAM. to get my real email address).
I'm actually interested in what the notion of an MMU for the 8051 looks like, so I'd be willing to try and help you figure this out.
-Jay Daniel
Like Jay Daniel, I have searched deep into Philips sites and have not found any datasheet for that family. Since it is targeted to serious criptographic applications, like digital passports, it may require NDA binds to get access to the documentation. If that is the case, you would be breaking such agreements by disclosing the datasheets to third parties.
Without having access to the documentation, I can only speculate on how virtual-to-physical addresses are resolved by the compiler and linker. You probably have a well-documented MMU programming interface by which you can dynamically map physical addresses (as pages or blocks probably) to virtual addresses (as segments probably) accessed by your program. You may also have a linker scripting interface to map static physical-to-virtual relocations that will allow the binary image to be loaded to physical rom locations with information to a loader that maps the MMU virtual addresses to the static physical objects. In either case, you should have compiler #pragmas or linker locator commands to control absolute physical location and force physical-to-virtual mapping of selected absolutely located segments.
Please if you can disclose any datasheet information, or can supply a link to the datasheet, do so.