ATmega328p Data Sheet (pdf)
Simulation of Blink
5 Ways to Blink
AarduinoCore AVR Source
Getting Started
Instruction Set
Inline Assembly
asm(R"( mov %[result], %[val] inc %[result] BREAK )" : /* write */ [result]"=r"(value) : /* read */ [val]"r"(value) );