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Re: [avr-libc-dev] Re: Far addresses in flash
From: |
Paul Schlie |
Subject: |
Re: [avr-libc-dev] Re: Far addresses in flash |
Date: |
Thu, 02 Jun 2005 19:12:55 -0400 |
User-agent: |
Microsoft-Entourage/11.1.0.040913 |
> From: "E. Weddington" <address@hidden>
>>> From: "E. Weddington" <address@hidden>
>>>
>>> You're right, that's the best, and most needed solution.
>>> However, *is* it possible to have 24-bit pointers in GCC
>>> (as opposed to 32-bit)? How difficult would that be?
>>
>> - Likely not worth it, as GCC also presumes data to be aligned on
>> power-of-two unit boundaries,
>>
> Such as 2^0.
> IIRC the AVR target has an alignment of 1.
2^0 = 1
2^1 = 2
2^2 = 4
...
Sorry should have more clearly stated "allocated/consuming"
(As it seems that an 3 byte datum will consume 4 bytes of storage
by default based upon GCC's type/mode assumptions, unless a bit of
tweaking is done to both the compiler and target implementation it
would seem; although agree it could be useful for a variety of data
types, but doesn't seem to be on top of GCC's apparent list of concerns.)