Classic/Legacy CodeWarriorのトピックRe: Accessing hard coded memory locations using C

Accessing hard coded memory locations using C

NeedHelp — Fri, 25 Apr 2008 02:32:49 GMT

Background:

The bootloader and OS are sharing the same UART and the OS needs to access some variables defined in the UART section of the bootloader.

Using the Keil compiler all I had to do was:

On the BL side:

unsigned int x _at_ SOME_HARD_CODED_VECTOR;

On the OS side:

unsigned int x _at_ SOME_HARD_CODED_VECTOR;

and both would essentially refer to the same address location.

However, code warrior doesnt support the _at_ keyword. How do I go about doing this in code warrior?

Basically how do I:

1. Define

int x;

int * y;

In the bootloader?

2. In such a way that I also have access to it from the OS? What would the code be in the OS side?

Please help! The datasheet shows accessing memory locations in assembly using P:$xxxx and D:$xxxx but how do I do it in C?

Thanks a bunch!

Re: Accessing hard coded memory locations using C

trytohelp — Fri, 25 Apr 2008 19:15:26 GMT

Hi,

We don't support the same syntax.

See below extract of the 56800x_Build_Tools_Reference.pdf manual.

Specifying Variable Addresses in C
The user can tell the compiler to specify the address of a variable in a C file using the :
operator. The constant value following the : operator is the word address of the global
variable (i.e., int OneReg : 0xBCD ; specifies that the global variable OneReg
resides at word address 0xBCD).

Hope this will help you

Pascal

Re: Accessing hard coded memory locations using C

NeedHelp — Fri, 25 Apr 2008 21:42:07 GMT

Thanks a bunch! And thank god its friday!

Re: Accessing hard coded memory locations using C

NeedHelp — Sat, 26 Apr 2008 00:14:09 GMT

Hi there!
I have yet another question:
How do I declare a "generic" pointer in codewarrior?
For example:
How should I declare
unsigned int * pTxData;
So that I can use it to point to data memory as well as program memory? Bare with me....

I have a macro:
#define mPktSend(_cmd, _pdata, _size) {uTxCmd = _cmd; pTxData = _pdata; uTxCnt = _size;}

I want to be able to use this macro to send data both from data and program memory locations.
mPktSend(0x00, uPktTxBuf, 1); //uPktTxBuf is in data memory. Right now this works just fine.

And at the same time be able to use it as:
mPktSend(0x02, (__pmem unsigned int *)(uPrgmAddr), 16); //send 16 bytes from program memory location beginning in uPrgmAddr - declared as unsigned int uPrgmAddr;
Right now this gives me an error. Doesnt like the fact I am sending a __pmem location to the macro.

Thank you!

Re: Accessing hard coded memory locations using C

trytohelp — Mon, 28 Apr 2008 14:28:40 GMT

For this request I think it should be better we use the CRM system.

Please use Freescale on line support web page.
- Go to following URL: http://www.freescale.com/TechSupport
- Click on Submit a Service Request to create a new one or Manage Existing Service Request.
- You will come to a login page.
- You can submit your request through the web from there or view the activities of a SR.

In the Service Request can you please provide us some information:

details about the Tool version used.
To do that you must:
* CW:
Start the IDE and click on Help | About Metrowerks CodeWarrior.
Click on Installed Products
Provide us all info displayed.
Or you can save them in a txt file.

Can you please provide us your example reproducing the issue ?

Regards

Pascal

Re: Accessing hard coded memory locations using C

NeedHelp — Mon, 28 Apr 2008 22:14:11 GMT

Thanks for the suggestion. I have done what you had told me to.

G'day.