S12 / MagniV MicrocontrollersのトピックRe: Extending XGATE RAM section?

Extending XGATE RAM section?

pittbull — Wed, 22 Feb 2006 17:49:39 GMT

Hello again,

I'm using Codewarrior 4.1 to write a combined S12X/XGATE application.
The .prm file defines a single XGATE RAM section...

SEGMENTS
....
RAM_XGATE = READ_WRITE 0xFB1000 TO 0xFB1FFF ALIGN 2
....
PLACEMENT
....
XGATE_CODE INTO RAM_XGATE;
....

...where the XGATE code is copied to for execution.
I want to increase this section by doing the following:

SEGMENTS
....
RAM_XGATE = READ_WRITE 0xFB1000 TO 0xFB1FFF ALIGN 2;
RAM_XGATE2 = READ_WRITE 0xFC1000 TO 0xFC1FFF ALIGN 2;
....
PLACEMENT
....
XGATE_CODE INTO RAM_XGATE, RAM_XGATE2;
....

Does this work?
In case it works, What happens when a fuction calls a function
in the other page? Does compiler/linker handle this correctly?

Thanks in advance
- pittbull

Re: Extending XGATE RAM section?

Steve — Wed, 22 Feb 2006 20:10:49 GMT

Hi pittbull,

Yes you can do what you propose but since the XGATE memory map isn't paged, you can also define a larger segment using global memory.

SEGMENTS
....
RAM_XGATE = READ_WRITE 0x0FB000'G TO 0x0FCFFF'G ALIGN 2
....
PLACEMENT
....
XGATE_CODE INTO RAM_XGATE;
....

If you use different ways of defining segments just be careful that you don't define the same segment twice.

Re: Extending XGATE RAM section?

pittbull — Wed, 22 Feb 2006 23:38:26 GMT

Hello Steve,

Thanks for the reply.

Are the global memory segments ('G) an undocumented feature? I can't find it in the manuals.

Re: Extending XGATE RAM section?

Steve — Wed, 22 Feb 2006 23:59:24 GMT

I don't think it is meant to be undocumented. It works in the debugger too when selecting an address in the memory window.

The options are:

default or 'L - logical address

'G - global address

'X - XGATE address (so you can define XGATE addresses in the prm file if needed)

Re: Extending XGATE RAM section?

CompilerGuru — Mon, 06 Mar 2006 04:09:59 GMT

When you list multiple segments to place the same section in, you might have to use the -OnBRA option as this setup can cause branch distances to increase. So when you get a fixup overload linker error, add -OnBRA.