Mixed C and Assembly style coding for K60 on Code warrior 10.3

[nasreenshaikh]

HI,

I am trying to write a delay function for k60 in codewarrior 10.3 using the __asm directive.The compiler gives me an error as follows

"expected '(' before '{' token" .The help manual for Codewarrior 10.3 states that

"To ensure that the C/C++ compiler recognizes the asm keyword, you must clear the ANSI Keywords Only checkbox in the C/C++ Language panel. "

But the C/C++ Build properties do not have an option for this particular setting.

In the Build properties panel under the ARM LTD windows GCC C compiler -->Miscellaneous-->Language standard If I change it from Compiler default to ISO C9 -ansi teh error related to asm directive goes away . But the rest of my C code throws up Multiple errors.

I know that asm directive is  ansi keyword. How do I enable my compiler to accept ANSI keywords?   

[Carlos_Musich]

Hi Nasreen,

GCC compiler will recognize asm directive by default, below you can see a very simple example. using asm instructions in a c file and also calling an assembly subroutine in a .s file.

in main.c

#include "derivative.h"

extern void _add();

int main(void)

{

asm ("mov r0, #0x0A");

asm ("mov r1, #0x03");

asm ("bl _add"); //using assembly code

}

in add.s

.global _add 

.text

.align 4 

_add:

  add r0, r0, r1

  bx lr

　

Hope this helps!

Carlos

[nasreenshaikh · Accepted solution]

Thank You Carlos

The asm directive does work with the GCC compiler. The problem was that I was using the syntax of HCS08 compiler as i was working on a project which uses both HCS08 and Kinetis K60. After using the correct syntax for GCC the error goes away. below is the function which I have written .

void delay10us(uint16_t us)

{

//uint16_t cnt;

asm volatile(

        "\n"

        "L_dl1%=:"   "\n\t"

        "mov r1, %1" "\n\t"

        "L_dl2%=:"   "\n\t"

        "sub r1, #1" "\n\t"

        "bne L_dl2%=""\n\t"

        "mov r2, %0" "\n\t"

        "sub r2, #1"     "\n\t"

        "bne L_dl1%=""\n\t"

        :: "r" (us), "r" (delay_count_us)

         );