Re: [avr-gcc-list] EF_AVR_LINKRELAX_PREPARED bit in e_flags

[Vidya Praveen]

Hi Joerg,

On 9/5/2012 12:25 AM, Joerg Wunsch wrote:
>> I am trying to introduce a new series for Tiny core. As I see 0xx
>> series is used for Mega and 1xx series is used for XMega now. If I
>> have to have 200 series for Tiny, I need to move the
>> EF_AVR_LINKRELAX_PREPARED to a different position.
>
>> I know this will cause binary incompatibility with older versions,
>> But I propose that we move this to 31st bit (e_flags is of type
>> ELF32_Word).
>
> Well, binary incompatibility is always bad, so I would avoid it.

I agree.

> Given that only very few "arch" numbers are actually used only so far,
> I don't think sacrificing bit 7 is really necessary.  How about
> placing the arch numbers for the tiny core series somewhere below the
> Xmega numbers?  If I'm not mistaken, so far we have
>
> 1, 2, 3, 4, 5, 6
> 25, 31, 35, 51 (which are derivatives of the former)
> 101, 102, 103, 104, 105, 106, 107
>
> As it is unlikely the old core will get any further development
> (beyond the 6), the number space above 69 is certainly not going to be
> used, ever.  So assigning the number space 8x/9x to the tiny core(s)
> should be safe.

I thought about using 9x but then I had an impression that 0xx series is
reserved for Mega! This sounds good to me.

While we are on this topic, I was wondering if we should also introduce a bit in
e_flags for -mshort-enums and add a compatibility check. Comments?

Regards
VP