topic Re: how to declare a global variable in assembly code with 56f8367 in S12 / MagniV Microcontrollers

how to declare a global variable in assembly code with 56f8367

Gaoya — Mon, 16 Aug 2010 20:42:19 GMT

hello,

I am using EVM8367 now, can somebody tell me how to declare a global variable in assembly code with 56f8367 and this variable can also be used in C ? thank you very much.

Re: how to declare a global variable in assembly code with 56f8367

CrasyCat — Tue, 17 Aug 2010 16:51:55 GMT

Hello

Assembler directives that can be used to create global variables are described in the 56800x_Assembler.pdf manual.

For instance you can define a buffer as follows:

    org x:
    GLOBAL F_S_BUF
F_S_BUF DS 12 ; 12-byte buffer

The GLOBAL directive instruct the assembler that the symbol needs to be visible from outside of the assembler module where it is declared. The F prefix is added in front of each global symbol by the compiler and is needed here as you intend to access the variable from ANSI C.

ANSI C declaration and access can be done as follows:

extern char _S_BUF[12];

int main(void) {
   _S_BUF[1] = 1;
   /* Your code here */
}

CrasyCat

Re: how to declare a global variable in assembly code with 56f8367

CrasyCat — Fri, 20 Aug 2010 03:00:30 GMT

This discussion was moved to a better location.