A note about the use of the trampoline in the AVR256. I was in trouble cause a wrong address in the upper 128K using the trampoline itself due to a linker error (I suppose). At the moment I don't use EICALL for this reason. If someone has news about this issue I'm very interested to fix the problem in my code. Thank you in advance
Rino Tallarico _________________________ via Pola 26 - 10135 Torino tel. +39 347 2261196 mailto: palmerinotallar...@vodafone.it -----Messaggio originale----- Da: avr-gcc-list-bounces+palmerinotallarico=vodafone...@nongnu.org [mailto:avr-gcc-list-bounces+palmerinotallarico=vodafone...@nongnu.org] Per conto di andrewhutchin...@cox.net Inviato: martedì 15 dicembre 2009 14.35 A: Sean D'Epagnier Cc: avr-gcc-list@nongnu.org; Weddington, Eric Oggetto: Re: [avr-gcc-list] Why are we using EICALL and EIJMP for AVR256? Thanks, it would be nice if this was documented. I noticed it when reviewing addressing modes and a omission in call patterns. void (*fptr)(); fptr = main; (*fptr)(); //Will use EICALL - should be CALL main which become readily apparent with inlined code. Andy ---- Sean D'Epagnier <geckosena...@gmail.com> wrote: > On 12/14/09, Andrew Hutchinson <andrewhutchin...@cox.net> wrote: > > The patterns for AVR mega 256 use EICALL an EIJMP > > > > Both require EIND to be set to provide upper address bits > > > > However, we are using linker trampolines for both, so in either case the > > 16 bit jump or call is to the trampolines. > > > > Are not the trampolines always located in first 128Kbytes? Thus we > > should be using ICALL and IJMP and not needing to set use EIND at all. > > > > What have I miss-understood? > > > > Hi, > > Yes this confused me a lot too, but the reason is because the > trampoline is not in the first 128kbytes for a bootloader, so if the > compiler uses eijmp and eicall, then it is possible to do indirect > calls there too, but it still works fine in normal code. > > Sean > > > > > Andy > > > > > > > > _______________________________________________ > > AVR-GCC-list mailing list > > AVR-GCC-list@nongnu.org > > http://lists.nongnu.org/mailman/listinfo/avr-gcc-list > > _______________________________________________ AVR-GCC-list mailing list AVR-GCC-list@nongnu.org http://lists.nongnu.org/mailman/listinfo/avr-gcc-list _______________________________________________ AVR-GCC-list mailing list AVR-GCC-list@nongnu.org http://lists.nongnu.org/mailman/listinfo/avr-gcc-list
