Re: [Sdcc-user] Optimizations

[Gernot.Fink <Ger...@mu...>]

On Don, 01 M=E4r 2001, cheng chung yan wrote:

Try to declare the Port -variable declare as SFR or volatile.

Big Warning:

Your Programm interferes with the Architekture of the 8051.

Ports ( all SFR )  are not accesible with indirect adressing.
You have to use constant Adresses for the access of a Port.

Independent of this some pointers in your programm are declared as char.


>dear all=20
> i need to prepare a self test program for hardware, that this program c=
hecks the Ports(P0 to P3) by the following subr.=20
>"
>unsigned char CheckPort(unsigned char Port)
>{
> bit RetFlag;
>
> Port =3D 0x55;
> if (Port=3D=3D0x55) {
>         Port =3D 0xaa;
>         if (Port=3D=3D0xaa) RetFlag =3D TRUE;
>        }
> RetFlag =3D FALSE;
>
> return RetFlag;
>}
>"
> where Port as the parameter of P0 or P1 or ...=20
> after compile, it shows the Optimizations warning as=20
>"
>crtxX51.c(72):warning *** conditional flow changed by optimizer 'crtxX51=
.c(66)':so said EVELYN the modified DOG
>crtxX51.c(72):warning *** conditional flow changed by optimizer 'crtxX51=
.c(68)':so said EVELYN the modified DOG
>"
> can i disable the Optimizations in these few C instructions?=20
> thanks=20
>yan=20
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--
MFG G.Fink