> Wiadomość napisana przez David Brown <[email protected]> w dniu
> 25.02.2019, o godz. 08:43:
>
>
> On 24/02/2019 18:29, Łukasz Kostka wrote:
>>> Wiadomość napisana przez David Brown <[email protected]> w dniu
>>> 24.02.2019, o godz. 14:58:
>>>
>>>
>>>
>>> On 24/02/2019 14:47, Łukasz Kostka wrote:
>>>>> Wiadomość napisana przez David Brown <[email protected]
>>>>> <mailto:[email protected]>> w dniu 24.02.2019, o godz. 12:13:
>>>>>
>>>>>
>>>>> This sort of thing has been an issue for all sorts of small
>>>>> microcontrollers, and all their compilers, since their inception. It is
>>>>> not solvable in an ideal way that gives maximal convenience to
>>>>> programmers and still results in efficient code. The only good solution
>>>>> is to move away from such cpu designs - there are very few reasons for
>>>>> choosing a core such as the AVR rather than an ARM, MIPS or RISC-V
>>>>> alternative. (You might choose the AVR device for its peripherals, or
>>>>> pin package, or power usage - but not for its core.)
>>>> Yes I know that AVR are old architecture.
>>>> I will move sooner or later to RISC-V or ARM. In fact bought some board
>>>> from sparkfun.
>>>> Does it mean that in newer cpu designs storing read only variables in
>>>> flash is easier than in AVR ?
>>>
>>> Most 16-bit and 32-bit cpus have a single address space. Since the same
>>> instructions are used to access data whether it is in ram or flash (or, in
>>> most cases, IO register areas), there is no longer any issue.
>>>
>>> The AVR uses different instructions for accessing data from flash and from
>>> ram, which is what causes the complications.
>> Thx for clarification
>> BTW. Do you know if any ARM cortex or RISC-V provide such instructions to
>> access data in flash / rodata ?
>
> No, neither ARM nor RISC-V has instructions to access data in flash or
> read-only data - that is /precisely/ the point. Such data is accessed
> exactly like ram data and any other data, using the same instructions and
> from the same single flat memory space.
Aha :-) So I just declare variable static const and voila. Well that is great.
Another strong paint to migrate to newer platforms.
