Follow-up Comment #6, patch #6352 (project avr-libc): The xxx_PF() functions modify the RAMPZ register, but on XMegas with EBI, RAMPZ influences also LD/LDD/ST/STD, making code after using xxx_PF() to access unintended data memory "pages".
In the attached file, in macros.inc, macro LPM_R0_ZPLUS_INIT is modified and macro LPM_R0_ZPLUS_FINI added, storing and restoring RAMPZ, for targets with __AVR_HAVE_RAMPD__ defined (which IMHO is unique indication of presence of EBI). Only LPM_R0_ZPLUS_FINI needs to be added to xxx_PF() functions (and documentation modified accordingly), as shown in the attached memcpy_PF(). All the xxx_PF() functions are affected and should be modified accordingly after consensus happens. As a cheaper alternative, RAMPZ could be simply zeroed as all "standard" RAM access in current avr-gcc is restricted to 16-bit addresses; whether this is a better option I leave to decide for the more experienced developers on this forum. This resolves https://savannah.nongnu.org/bugs/?func=detailitem&item_id=25120 which thus could be closed as duplicate (the issue with RAMPZ mods being non-interrupt safe is resolved by saving RAMPZ in the standard interrupt prologue/epilogue as of avr-gcc version 4.3+). (file #20859) _______________________________________________________ Additional Item Attachment: File name: memcpy_PF.zip Size:5 KB _______________________________________________________ Reply to this item at: <http://savannah.nongnu.org/patch/?6352> _______________________________________________ Message sent via/by Savannah http://savannah.nongnu.org/ _______________________________________________ AVR-libc-dev mailing list AVR-libc-dev@nongnu.org http://lists.nongnu.org/mailman/listinfo/avr-libc-dev
