S12 / MagniV MicrocontrollersのトピックRe: using array declared in "C" code in assembly for S12X

using array declared in "C" code in assembly for S12X

Vicky — Mon, 16 Jun 2008 23:38:28 GMT

Hi,

I have a requirement which is quite different which i never used earlier.

1. Declared a array in a file, test1.c

unsigned int Store[10]; //Assume unsigned int takes 2 bytes of data

2. Now, I need to update store array with content of PC, SP, X, Y and other registers. //Assume, Store[] variable and copy logic would be in same file. I hope it should not be issue either

Question:

1. Is it possible to perform step2 above?

2. If its possible, can I have a short example for same.

Regards

Vicky

Re: using array declared in "C" code in assembly for S12X

EmbeddedCoder — Wed, 18 Jun 2008 16:49:04 GMT

Hi Vicky,

It is certainly possible to grab the stack pointer content and store this in an Array via C.

I do something similar with the macro below:

ASM_STORE_STACK_PTR(pu8_stack);

Where the macro is defined as:

#define ASM_STORE_STACK_PTR(p_stack) {__asm STS p_stack;}

you will need to check the S12 assembler manual, but there will be other assembler commands to grab the other registers.

Good luck!

Re: using array declared in "C" code in assembly for S12X

EmbeddedCoder — Wed, 18 Jun 2008 17:00:29 GMT

I looked this up for you:

STAA will store the Acc A Reg

STAB will store the Acc B Reg

STX will store the Index X Reg

STY will store the Index Y Reg

so you can create other macros to store these values for you, as shown below:

#define ASM_STORE_ACC_A(p_acc_a) {__asm STAA p_acc_a;}

#define ASM_STORE_ACC_B(p_acc_b) {__asm STAB p_acc_b;}

#define ASM_STORE_IX_X(p_x) {__asm STX p_x;}

#define ASM_STORE_IX_Y(p_y) {__asm STY p_y;}

I'm not sure what storing the program counter will do for you as it will be the address of the place where you store the values?

Do you mean you want to store the program counter contained on the stack (i.e. the calling function)?

Re: using array declared in "C" code in assembly for S12X

Xbot — Tue, 24 Jun 2008 16:48:01 GMT

Id suggest you store it in a struct...

see here:

http://forums.freescale.com/freescale/board/message?board.id=8BITCOMM&message.id=10109