On Jul 15, 1:16 am, Paul Keinanen <keina...@sci.fi> wrote:
> On Mon, 14 Jul 2008 11:50:22 -0500, "serene" <sere...@gmail.com>
> wrote:
>
> >  Am using PSoC designer with complier IMAGECRAFT.
> >  I want to call a C function for CRC8_CCITT from an assembly ISR.
> >  I have to pass an argument and the funtion should return a value also.
>
> Are you absolutely sure that the routine is re-entrant ?
>
> Does the C-compiler offer some extensions for writing ISRs in C ? If
> so, write your ISR in C and call that function from there, unless the
> manual restricts what can be called from the ISR.
>

Yes, it does.
This is an example of interrupt written in C for Imagecraft:

#pragma interrupt_handler Timer_ISR
void Timer_ISR(void)
{
    PRT1DR &= 0xbf;
    sysclock++;
    PRT1DR |= 0x40;
}

In addition the corresponding interrupt vector should contain the
proper jump, like:

    org   20h                      ;PSoC Block DBB00 Interrupt Vector
    // call	void_handler
    ljmp	_Timer_ISR

For PsoC Designer this is in boot.asm file

On Mon, 14 Jul 2008 11:50:22 -0500, "serene" <serene6@gmail.com>
wrote:

>  Am using PSoC designer with complier IMAGECRAFT.
>  I want to call a C function for CRC8_CCITT from an assembly ISR.
>  I have to pass an argument and the funtion should return a value also.

Are you absolutely sure that the routine is re-entrant ?

Does the C-compiler offer some extensions for writing ISRs in C ? If
so, write your ISR in C and call that function from there, unless the
manual restricts what can be called from the ISR.

If the C-compiler does not support ISR extensions, it is quite likely,
that the library may have all kinds of re-entrancy problems.

If you do not have the sources for the function, link it to an
ordinary program and disassemble it or step through it to check for
any redundancy issues. You will also notice what calling convention is
used.

Paul

Rich Webb wrote:
> On Mon, 14 Jul 2008 11:50:22 -0500, "serene" <serene6@gmail.com> wrote:
> 
>> hi
>>  Am using PSoC designer with complier IMAGECRAFT.
>>  I want to call a C function for CRC8_CCITT from an assembly ISR.
>>  I have to pass an argument and the funtion should return a value also.
>>
>> Can somebody help me to do this.....
> 
> I haven't used their PSoC compiler but based on the Imagecraft compilers
> that I do use, check the help file in the section "Programming the [  ]"
> for the "Inline Assembly" topic and in the section "C Runtime
> Architecture" for "Assembly Interface and Calling Conventions." 
> 
Failing that, nearly all C compilers will compile to assembly.  If the 
manual doesn't help, or if you want to make sure, compile some code to 
assembly and see (a) how it calls functions and (b) how called functions 
get their parameters.

Generally a compiler will put have the processor put variables onto the 
stack or into registers to pass them as parameters, and it will put 
variables into registers (or into some special 'return value area' in 
memory if they're really register-starved) to return values.

-- 

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

On Mon, 14 Jul 2008 11:50:22 -0500, "serene" <serene6@gmail.com> wrote:

>
>hi
>  Am using PSoC designer with complier IMAGECRAFT.
>  I want to call a C function for CRC8_CCITT from an assembly ISR.
>  I have to pass an argument and the funtion should return a value also.
>
>Can somebody help me to do this.....

I haven't used their PSoC compiler but based on the Imagecraft compilers
that I do use, check the help file in the section "Programming the [  ]"
for the "Inline Assembly" topic and in the section "C Runtime
Architecture" for "Assembly Interface and Calling Conventions." 

-- 
Rich Webb     Norfolk, VA

hi
  Am using PSoC designer with complier IMAGECRAFT.
  I want to call a C function for CRC8_CCITT from an assembly ISR.
  I have to pass an argument and the funtion should return a value also.

Can somebody help me to do this.....

Thanks,
serene