S12 / MagniV MicrocontrollersのトピックDefining memory segment in PRM file

Defining memory segment in PRM file

Xbot — Wed, 28 May 2008 21:26:54 GMT

hi all,

I am defining labels inside the .prm file so i can use __SEG_START or END for a particular memory segment. Ive read tn2281 but it doesnt seem to work.

for instance:

SEGMENTS

TESTMEM = READ_WRITE 0x140000 TO 0x77FFFF FILL 0x3F;

END

PLACEMENT

TestMemory INTO TESTMEM;

END

usage:

extern char __SEG_START_TestMemory[];

#define TestMemoryStart __SEG_START_TestMemory

char* StartAddress = (char*)TestMemory;

I dont seem to get the value for StartAddress. Is there something I missed?

I am using EVB9S12XEP100 board , CW4.5

Re: Defining memory segment in PRM file

CrasyCat — Thu, 29 May 2008 20:02:31 GMT

Hello

This should work

Can you please check your .map file.

Is there anything allocated in section TestMemory?

Or is the section empty?

CrasyCat

Re: Defining memory segment in PRM file

Xbot — Mon, 02 Jun 2008 15:24:30 GMT

It is is covered by other labels specifically EEPROM_14 = READ_ONLY 0x140800 TO 0x140BFF...etc.

Re: Defining memory segment in PRM file

CrasyCat — Mon, 02 Jun 2008 20:40:11 GMT

Hello

Memory areas (segments) defined in the PRM file should not overlap.

Here I assume your objects are allocated in EEPROM_14 and nothing comes into TestMemory.

This is the reason you cannot retrieve its start/end address.

Also for HCS12X it is not recommended to defined memory area going across several banks.

I am not sure to understand what you are trying to achieve here, but if the purpose is to test memory on several pages I would rather recommend you to proceed page after page.

HCS12X is a banked architecture after all.

You can decide to go with global addresses, but then also, make sure you do not define a segment (memory area) across a 64K global page boundary.

CrasyCat

Re: Defining memory segment in PRM file

Xbot — Tue, 03 Jun 2008 20:37:19 GMT

Hello,

I would like to define a "start" and "end" labels to be used for mpu descriptors. Probably this is not the best solution since code size increase all the time(new versions, etc...).

Is there a better solution to this? The purpose of having labels is to not constantly change descriptor ranges.

thanks,

Re: Defining memory segment in PRM file

Xbot — Wed, 04 Jun 2008 19:12:46 GMT

hello all,

sorry for the trouble... also want to make things clear. from the memory map below, is it arranged in this order?

|---------------- |---> 0x2002

|---------------- |

|-----------------|

| stack |

|default ram |

|xgatexx |

|shared |--->0x3fef

------------------

prm:

SEGMENTS

RAM = READ_WRITE 0x2002 TO 0x3FEF

PLACEMENT

stack,default_ram,xgatexx,shared INTO RAM

Re: Defining memory segment in PRM file

CrasyCat — Fri, 06 Jun 2008 16:08:24 GMT

Hello

I am not sure I understand what you want to do here.

Are you trying to retrieve start address of stack and end address of shared to put them in a descriptor?

Is that what you want to do?

CrasyCat

Re: Defining memory segment in PRM file

Xbot — Fri, 06 Jun 2008 17:10:21 GMT

Yes and no.

SSTACK, DEFAULT_RAM, SEGDRV_XGATE_SHARED, SHARED_DATA,
INTO RAM;

I will assign a descriptor for SSTACK, another descriptor for SHARED_DATA. Is this possible? can i retrieve the start and end address for SHARED_DATA even if it doesnt have any objects yet? And Is this method possible? I will also, assign descriptors for EEPROM in the same manner.

Hoping for your generousity,

Re: Defining memory segment in PRM file

CrasyCat — Fri, 06 Jun 2008 19:44:24 GMT

Hello

You can retrieve stack start and end address as follows:

extern char __SEG_START_SSTACK [];
extern char __SEG_END_SSTACK [];

#define Start_Stack __SEG_START_SSTACK
#define End_Stack __SEG_END_SSTACK

For SHARED_DATA and EEPROM, if there are no objects allocated in these segment, the __SEG_START and __SEG_END symbols will be set to 0.

So you may have to test the value of the pointer and in case of a NULL pointer there is nothing in there and you do not need to initialize a descriptor.

CrasyCat

Re: Defining memory segment in PRM file

mikoran — Wed, 13 Aug 2008 09:41:15 GMT

Can I ask where could we find the declaration for __SEG_START_SSTACK[ ] and __SEG_END_SSTACK[ ]?

Since we are using extern char __SEG_START_SSTACK [];

so we expect that it is declared somewhere.

Thanks

Re: Defining memory segment in PRM file

CrasyCat — Wed, 13 Aug 2008 18:43:15 GMT

Hello

These symbols are Linker defined symbols.

The linker determines the value of these symbols at link time.

They are not explicitly defined anywhere in a source file, but when the linker sees a reference to these symbols he just puts the corresponding address in the code.

CrasyCat

Re: Defining memory segment in PRM file

mikoran — Thu, 14 Aug 2008 15:04:34 GMT

ok thanks a lot..

Re: Defining memory segment in PRM file

MusikA — Mon, 09 Feb 2009 17:12:19 GMT

Hi,

I'm a newbie to the embedded world. I have here the PRM file.

SEGMENTS
BODY_METHOD3 = READ_ONLY 0xFE8400 TO 0xFE8BF5;
END

PLACEMENT
BODY_METHOD3_SECTION INTO BODY_METHOD3;
END

I'm trying to calculate a CRC16-CCITT for the data in BODY_METHOD3, could I possible use __SEG_START_BODY_METHOD3_SECTION as an array to the BODY_METHOD3 data? If ok, how will it be implemented?

Thanks......

Re: Defining memory segment in PRM file

CrasyCat — Tue, 10 Feb 2009 16:33:34 GMT

Hello

This is a completely different question. For clarity purpose it is recommended to create a new thread for new questions.

__SEG_START_BODY_METHOD3_SECTION can be used to retrieve the start address of section BODY_METHOD3_SECTION .

The linker will simply place the symbol at the section start address.

It is then up to you to do whatever to want with that array/pointer.

CrasyCat