Re: [avr-gcc-list] Initilizing complex const arrays : syntax ?

[Dave Hansen]

From: David Kelly <address@hidden>
[...]
>     char buffer[4];
>     uint8_t i;
>     strncpy_P( buffer, PGM_P("000"), 3 );
>     i = 2;
>     while(x) {
>         buffer[i--] = x%10 + '0';
>         x = x/10;
>     }
>     putchar(buffer[0]);
>     putchar('.');
>     putchar(buffer[1]);
>     putchar(buffer[2]);
>
> In the above I find myself wishing for the FORTH /mod operator. Avr- gcc 
> calls exactly the same routine for division or modulo and stores  the 
> desired result. In assembly we could store both but I don't see  how to get 
> at both from C. Is possible the compiler could optimize it  but plain -O 
> didn't in recent tests.

Try something like

  #include <stdlib.h>
  ...
  div_t qr;

    while(x) {
        qr = div(x,10);
        buffer[i--] = qr.rem + '0';
        x = qr.quot;
    }

I'm not certain this is optimal.  I haven't looked closely, but it looks 
like it should be.  It certainly has the opportunity to be.

Regards,
  -=Dave