topic Re: Inline assembly for Codewarrior in CodeWarrior for MCU

Inline assembly for Codewarrior

clayhowell — Fri, 22 Mar 2013 20:10:08 GMT

Hi,

This may be a real stupid question but I can’t figure it out. I’m using Special Edition Codewarrior Eclipse for MCUV10.3 and programming the 9S08PA4. I started a new bareboard project and want to add some inline assembly to the code. This simple code won’t compile, I get “Unknown Opcode C18701” for both MOV and DBZN. This is the only code in the main file:

#include <hidef.h> /* for EnableInterrupts macro */

#include "derivative.h" /* include peripheral declarations */

int delaycomm;

void main(void) {

EnableInterrupts;

/* include your code here */

asm

{

MOV #$FF,delaycomm;

LoopHere:

NOP;

DBNZ delaycomm,LoopHere;

}

for(;;) {

__RESET_WATCHDOG(); /* feeds the dog */

} /* loop forever */

/* please make sure that you never leave main */

}

Re: Inline assembly for Codewarrior

kef — Sat, 23 Mar 2013 08:40:30 GMT

Message is probably caused by using other than Tiny memory model, in which static storage variables are placed at address >= 0x100, and as a result MOV can't be used.

Error message is misleading. I tried to compile the same snippet in CW 6.3. It produced

Error : C18700: Unknown Opcode Operand Combination: Opc.:MOV/Dest.:Ext/Source:Imm8.

, which makes sense.

To place variables in zero page use DATA_SEG pragma like this:

#pragma DATA_SEG __SHORT_SEG MY_ZEROPAGE

int delaycomm;

#pragma DATA_SEG DEFAULT // restore memory model default placement

Re: Inline assembly for Codewarrior

clayhowell — Sat, 23 Mar 2013 21:46:51 GMT

Hey thanks. Adding the pragma's does the trick. Thanks so much for the insight.