Re: [avr-gcc-list] do-while problem

[Vaclav Carnogursky]

Hello,

There is no problem with assembler,  you just forgot 'volatile' directive
in declaration of ABC variable.
Should be:

volatile uint8_t ABC ;

Vasso

Arne Lynge Madsen wrote:

> Hi,
>
> I just realized that there migth be a bug in the generated assempler...
>
>
> do
> {
>  } while (ABC == 0x01 );
>
> 166: 80 91 60 00    lds r24, 0x0060
> 16a: 81 30                cpi r24, 0x01 ; 1
> 16c: f1 f3                    breq .-4       ; 0x16a
>
> ABC is updated by an interrupt routine. breq.-4 only jumps back to the
> cpi statement, so the updated ABC is not taken into account. Loops
> forever!
>
>
> do
> {
>  } while (somefunction() != 0);
>
> 132: 86 d1        rcall .+780     ; 0x440
> 134: 88 23        and r24, r24
> 136: e9 f7        brne .-6       ; 0x132
>
> somefunction() returns ABC. Here brne.-6 jumps back to rcall. It works!
>
> I currently use these packages:
> binutils-2.11.2
> gcc-3.0
> avr-libc-20011208
>
> Questions:
> Where is this error located? binutils, gcc or avr-libc?
> Could it be corrected in later versions, if so which one?
> Where to report the error?
>
> Best regards
> Arne
>
>
>
>
> avr-gcc-list at http://avr1.org
>
> .
>
>  



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