topic Re: Assembly code porting from GCC to CodeWarrior in S12 / MagniV Microcontrollers

Assembly code porting from GCC to CodeWarrior

embitel — Fri, 06 Jul 2012 14:48:34 GMT

Please let me know how to port the below code from GCC to CodeWarrior. This whole code is embedded in C code.

__asm__ __volatile__ (
            "ldd   #512\n"
            "tthclr:\n"
            "movw   #0, 2,y+\n"
            "dbne   d, tthclr\n"
            :
            : "y"(ram_data)
            : "d");

The problem is with the last three lines of code.

            :
            : "y"(ram_data)
            : "d");

Thank you,

Deepak

Re: Assembly code porting from GCC to CodeWarrior

MJW — Thu, 29 Oct 2020 09:27:09 GMT

Hello Deepak,

from looking at the code I don't see a real reason to write this in assembly language; I would just re-write this loop in C.

But if you are looking for an easy way to have the exact same code in Codewarrior, this should do:

asm {        ldy  #ram_data        ldd  #512tthclr:        movw #0,2,y+        dbne d,tthclr}

HTH,

MJW

Re: Assembly code porting from GCC to CodeWarrior

embitel — Fri, 06 Jul 2012 15:29:48 GMT

Hello MJW,

Thanks for the solution. I have one doubt. What is the meaning of "d" in the last line of code.

            :
            : "y"(ram_data)
            : "d"

Regards,

Deepak

Re: Assembly code porting from GCC to CodeWarrior

MJW — Fri, 06 Jul 2012 15:36:46 GMT

Hello Deepak,

If I remember correctly, the last line tells gcc that the register "d" was changed ("clobbered") in the inline assembly portion.

HTH,

MJW

Re: Assembly code porting from GCC to CodeWarrior

embitel — Fri, 06 Jul 2012 15:43:05 GMT

Hello MJW,

How can we replicate that same behaviour of "d" in CodeWarrior? As I am just porting, I would like to have all the code.

Regards,

Deepak