Function pointer with code banking

so the money might be better spent in moving to an ARM or something... ;-)

Let me sugges a "something": a seriously pumped-up 8051. DS80C390 contiguous mode, for one, would seem to be exactly the kind of remedy for that kind of problem. It has its own little quirks, but compared to doing 8 x 32K code banking on a classic 8051, it's heaven on earth.

so the money might be better spent in moving to an ARM or something... ;-)

Let me sugges a "something": a seriously pumped-up 8051. DS80C390 contiguous mode, for one, would seem to be exactly the kind of remedy for that kind of problem. It has its own little quirks, but compared to doing 8 x 32K code banking on a classic 8051, it's heaven on earth.

The most valuable metric would probably be inter-bank call count. I haven't thought about it in detail; maybe you also want to measure parameter space needed. But the primary metric is probably just calls out of the current bank.

So, the tool would have a big 2D matrix, indexed by module (segment), with a count of all calls to other segments. Each segment must be assigned to a bank. Minimize the total cost by changing bank assignments to reduce the inter-bank count. For extra credit, allow manual "nailing down" of bank assignment for particular modules that have particular requirements (say, a need for speed that forces them into the common bank).

I'm sure someone's project metrics count entry points, but it seems unlikely that they'd organize modules into groups in this manner.

In one of my particular cases, I've only got about 90KB of code, hardly a reason to move to an ARM7 or whatever. (Not that it's a possibility, because many hundreds of thousands of deployed units exist with the current processor.) But even with a small program, it's still an annoying manual process to assign .c files to banks. Add some code, or even debug statements, the bank overflows, and the linker just quits. There's no automatic reassignment or balancing at all.

uVision already has a feature that can tell you most of this kind of thing. The source browser creates a database of functions and callers and callees.

To view it...

1. Make sure that Browse Information is enabled in the Options For Target - Output tab. Then, re-build your project.
2. Select Source Browser from the View Menu.
3. Select Functions from the Browser Window. This shows all the functions in your program. Click on the Uses column to sort by the number of times the function is called.
4. Right-click on a function to change the display to show the call tree or the caller tree for that function.

The fundamental limitation that I find with the Sourec Browser is that there's no way to export any results from it. :-(
It all has to be done interactively in the GUI - and is all lost when you close the GUI. :-(


MSVC used to have a command-line tool for querying their browser database ("bscdump", IIRC) - something like that would be really useful!

hi
for this function pointer with code banking problem ,i come to know that OVERLAY directive can Generate table which has return address of function pointers.

so any body know how to set this OVERLAY directive in keil?

regards
Niraj