In-line assembly in Codewarrior for 8 bit v6.2

[RakeshParekh]

Hi,

I am developing code using MC9S08QD2 and codewarrior v6.2

For certain critical operations, I want my generated code to be optimized in size and execution speed.

Are there ready to use intrinsic functions defined in codewarrior to use assembly instructions like ROR - rotate right through carry, SEC - set carry, CLC - clear carry etc?

As I do not find these intrinsic function, I tried to put down macro definition for these purpose.

However it does not compile.

For ex.
unsigned char VarC;
#defined RotateRight(x) {__asm ROR x;}

void main (void)
{
:
:
RotateRight(VarC);
:
}

I get compiler error messages C18700 and C18701.

How to resolve it?

Same error messages go away if I first transfer operand to accumulator and work on accumulator.

Why so?
 
Kindly advice asap.
 
Thanks and regards,
 
Rakesh

[CompilerGuru · Accepted solution]

The ROR instruction does only support DIR (meaning 8 bit addresses) and not EXT (meaning 16 bit addresses). Therefore either allocate VarC in a __DIRECT_SEG area (and tell the compiler), load, rotate in a register, rotate the register and store it back to VarC or load the address of VarC into H:X and use "ROR ,X".

I'm guessing that placing the variable into a __DIRECT_SEG segment is the best way to go as this is an optimization task.

E.g.

#pragma push#pragma DATA_SEG __SHORT_SEG MY_NEAR_DATA_SEG  // must be mapped in the prmunsigned char VarC;#pragma pop

 

Check the ROR access details in the HCS08 reference manual and AN2093.pdf also contains samples using the direct page.

Daniel

[RakeshParekh]

Pls. ignore Solved Tag.

It was by mistake.

The issue is not solved.

Thanks and regards,

Rakesh

[RakeshParekh]

Hi,

VarC is declared in direct page area. In map file, its location is 0x87.

But still error comes.

Is #pragma push and #pragma pop necessary in definition?

what they do?

Kindly advice.

Thanks and regards,

Rakesh

[CompilerGuru]

> VarC is declared in direct page area. In map file, its location is 0x87.

Is is declared in a section with a __SHORT_SEG qualifier? The compiler does not read map files .

It's the other way round, if the variable is placed in a  __SHORT_SEG section and that section is placed in the prm file into the first 256 bytes, then the map file will show an address < 256.

Here a simplistic snippet which works for me:

#pragma DATA_SEG __SHORT_SEG MY_ZEROPAGEunsigned char VarC;#define RotateRight(x) {__asm ROR x;}void main (void){  RotateRight(VarC);}

Also note the manuals in the help and help\pdf folders.

Daniel