Dmitry Xmelkov a écrit:
Follow-up Comment #2:What is the necessity to add memory barrier for _NOP()? Common usage, like: PORTB |= 1; _NOP(); PORTB &= ~1; is safe, as hardware registers are volatile.
Question is whether or not NOP should be allowed to be moved across ordinary memory moves. For SEI and CLI, for example, I think this is not wanted in general. NOP is less intrusive than SEI / CLI, of course, but avr-gcc emits __builtin_avr_nop() with a memory clobber: http://gcc.gnu.org/viewcvs/trunk/gcc/config/avr/avr.md?revision=195151&view=markup#l5938 _______________________________________________ AVR-libc-dev mailing list AVR-libc-dev@nongnu.org https://lists.nongnu.org/mailman/listinfo/avr-libc-dev
