zero out bitvars area in cstartup

Hi there,

I'm trying to zero out the bitvars area in a 8052 cpu in the 'cstartup'
file.

My compiler (IAR) has two "assembler operators" SFB(..) and SFE(..)
that gives me the start and end of the "bit addresses" that needs to be
cleared.


MOV     R0,#SFB(BITVARS)
SJMP    CLEAR_BITVAR_2
CLEAR_BITVAR:
CLR     R0
INC     R0
CLEAR_BITVAR_2:
CJNE    R0,#SFE(BITVARS),CLEAR_BITVAR

This code doesnt seem to work.
I'm not sure but it's probably the "CLR R0" line that's the problem.
Regards

Beach wrote:

> Hi there,
>
> I'm trying to zero out the bitvars area in a 8052 cpu in the 'cstartup'
> file.
>
> My compiler (IAR) has two "assembler operators" SFB(..) and SFE(..)
> that gives me the start and end of the "bit addresses" that needs to be
> cleared.
>
> MOV     R0,#SFB(BITVARS)
> SJMP    CLEAR_BITVAR_2
> CLEAR_BITVAR:
> CLR     R0
> INC     R0
> CLEAR_BITVAR_2:
> CJNE    R0,#SFE(BITVARS),CLEAR_BITVAR
>
> This code doesnt seem to work.
> I'm not sure but it's probably the "CLR R0" line that's the problem.
> Regards

MOV     R0,#SFB(BITVARS)
SJMP    CLEAR_BITVAR_2
CLEAR_BITVAR:
CLR     R0   ; ******* This is wrong *****
INC     R0
CLEAR_BITVAR_2:
CJNE    R0,#SFE(BITVARS),CLEAR_BITVAR

my 8051 asm is rusty but try:
CLR     @R0

or
CLR A
MOV @R0,A

you need to use R0 as a pointer (indirect move)

If I am wrong try the forum at www.8052.com