Re: [Mspgcc-users] [msp430] Anybody notice some of these bugs?

[Dmitry K.]

as 7 Apr 2004 03:33 Sergei Sharonov wrote:
>
> -------------------
> volatile short *pbuf, *plast;
>
> int main(void)
> {
>   short buf[10];
>   pbuf = buf;
>   plast = buf + 10;
>   while(pbuf < plast);
>   return 0;
> }
>
> void foo(void) /* called from interrupt */
> {
>   if(pbuf <= plast)  *pbuf++ = 0;
> }
>
> -----------
> Compiles into:
>
>   while(pbuf < plast);
>       4054:   0f 9e           cmp     r14,    r15     ;
>       4056:   fe 2b           jnc     $-2             ;abs 0x4054
>
> > 2. volatile var updates every time after 'volatile value' updated.
>
> See above.
>

Compiler is right.

Variables in buf[10] are volatiles in this example.
Try another place of word `volatile':

   short * volatile pbuf, * volatile plast;

Now volatiles are pointers:

   .L2:
        mov     &pbuf, r14
        mov     &plast, r15
        cmp     r15, r14
        jlo     .L2

Best regards.