topic Re: Storage variable in the specific location in memory in Classic/Legacy CodeWarrior

Storage variable in the specific location in memory

admin — Thu, 01 Mar 2007 04:51:26 GMT

Hello,
how I can storage variable in the specific location in memory?
For example I have
int x; //I want have variable x on address 0x200
but how it say to compiler?
I'm using Code warrior 8.0 and DSP56F805
please help.
Regards
MP

Re: Storage variable in the specific location in memory

mbandini — Thu, 01 Mar 2007 23:28:32 GMT

unsigned char CTRLBYT @0x0048mailto:i@0x200" rel="nofollow" target="_blank

Re: Storage variable in the specific location in memory

admin — Fri, 02 Mar 2007 00:25:49 GMT

it doesn't work.

Re: Storage variable in the specific location in memory

CompilerGuru — Sat, 03 Mar 2007 07:53:53 GMT

The @ syntax is supported by the 8/16 bit tools (HC08/HC12).
I never used DSP56F805, so I cannot really say anything useful specific to this compiler, but I would suspect that you can place some variables into a specific section and then place this section in the lcf file.

If you do not really need a variable, just a way to read/write from a certain memory location, you can use a macro instead of a variable with any ANSI-C compiler.
#define MyVar (*(unsigned char*)0x200)
The actual code using it looks just as if a MyVar variable was defined as unsigned char, what's not so good is that there wont be any debug information tough, also the "variable" wont be initialized, of course.

Daniel

Re: Storage variable in the specific location in memory

Vilbcam — Wed, 06 Jun 2007 13:19:37 GMT

Hello, Im starting at 56F801, coming from 8 bits microcontrollers and I just cant have it right, I want to write in assembler and need to use variables, but I dont know where to ( and how ) define them.

How did you do? Did you find out how to define it?

Thanks