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Re: [avr-gcc-list] May avr-gcc emit EIJMP/EICALL?
From: |
Denis Chertykov |
Subject: |
Re: [avr-gcc-list] May avr-gcc emit EIJMP/EICALL? |
Date: |
Thu, 13 Oct 2011 17:16:12 +0400 |
2011/10/13 Jan Waclawek <address@hidden>:
>>The jump targets in jump tables from switch_case/.ctors/.dtors are located in
>>lower flash and their entries are gs() and use relaxation magic to have
>>jumping
>>pads generated.
>
> AFAIK, the linker creates the trampoline/jumptable regardless of relaxation.
> It's just that in certain (in practice most) cases this process is broken
> UNLESS relax is used.
> http://www.avrfreaks.net/index.php?name=PNphpBB2&file=viewtopic&p=707285#707285
>
>
>
>>Bottom line is that there is no need to ever touch or use EI gadgets, and EI
>>should be removed from the compiler like so:
>
> As it is now, yes. But there might have been a reason for the EI back then.
>
> Imagine for example that all targets of indirect jumps are within one 64kW
> "segment". Then, the "segment" register EIND could be set once at the
> beginning and left so forever; and there's no need for the trampolines.
>
I'm agree.
Right now the AVR port have a support only for 16bits addressing for
program memory.
It is a 128k bytes and 64k words.
Lets say "The current AVR ABI require EIND == 0". If user change it
implicitly then EIND must be restored to 0.
Denis.
- [avr-gcc-list] May avr-gcc emit EIJMP/EICALL?, Georg-Johann Lay, 2011/10/12
- Re: [avr-gcc-list] May avr-gcc emit EIJMP/EICALL?, Boyapati, Anitha, 2011/10/13
- Re: [avr-gcc-list] May avr-gcc emit EIJMP/EICALL?, Georg-Johann Lay, 2011/10/13
- Re: [avr-gcc-list] May avr-gcc emit EIJMP/EICALL?, Jan Waclawek, 2011/10/13
- Re: [avr-gcc-list] May avr-gcc emit EIJMP/EICALL?,
Denis Chertykov <=
- Re: [avr-gcc-list] May avr-gcc emit EIJMP/EICALL?, Georg-Johann Lay, 2011/10/13
- Re: [avr-gcc-list] May avr-gcc emit EIJMP/EICALL?, Jan Waclawek, 2011/10/13
- Re: [avr-gcc-list] May avr-gcc emit EIJMP/EICALL?, Denis Chertykov, 2011/10/14
- Re: [avr-gcc-list] May avr-gcc emit EIJMP/EICALL?, Georg-Johann Lay, 2011/10/14
- Re: [avr-gcc-list] May avr-gcc emit EIJMP/EICALL?, Jan Waclawek, 2011/10/14
- Re: [avr-gcc-list] May avr-gcc emit EIJMP/EICALL?, Georg-Johann Lay, 2011/10/14
- Re: [avr-gcc-list] May avr-gcc emit EIJMP/EICALL?, Jan Waclawek, 2011/10/14
- Re: [avr-gcc-list] May avr-gcc emit EIJMP/EICALL?, Georg-Johann Lay, 2011/10/31
- Re: [avr-gcc-list] May avr-gcc emit EIJMP/EICALL?, Denis Chertykov, 2011/10/14
- Re: [avr-gcc-list] May avr-gcc emit EIJMP/EICALL?, Marek Michalkiewicz, 2011/10/14