1.5 KiB
1.5 KiB
& 'C:\Program Files (x86)\Arduino\hardware\tools\avr\bin\avr-objdump.exe' -S "C:\\Users\\Lehtinen\\AppData\\Local\\Temp\\arduino_build_119176/test.ino.elf" > c:\temp\koe.txt
cli // 1 clock
PORTB = *ptr; // is this atomic? probably, because ptr is 6-bit pointer. nope...
f98: e0 91 26 01 lds r30, 0x0126 ; 0x800126 <__data_end> // 2 clocks
f9c: f0 91 27 01 lds r31, 0x0127 ; 0x800127 <__data_end+0x1> // 2 clocks
fa0: 80 81 ld r24, Z // 1 clock
fa2: 85 b9 out 0x05, r24 ; 5 // 1 clock
sei // 1 clock
500ns
cli
mov r31, r1
mov r30, gpior0
ld r24, Z
out 0x05, r24
sei
375ns
register as variable
- https://forum.arduino.cc/index.php?topic=43760.5
- http://www.nongnu.org/avr-libc/user-manual/FAQ.html#faq_regbind
- volatile register unsigned char my_register asm("r2");
- https://www.avrfreaks.net/forum/binding-variable-register
running code from ram
- https://forum.arduino.cc/index.php?topic=425962.0
- https://forum.arduino.cc/index.php?topic=470631.0
- "AVRs are Harvard architecture CPUs, so they CANNOT run code out of RAM, so that directive can't possibly do anything of any value whatsoever."
- "Yes, Harvard IS the reason. A Harvard CPU, by definition, has separate code and data memory spaces. They execute code from one memory, and fetch data from a different memory. What you're seeing is most likely the compiler pretending the directive can do what you want, but the linker doing the only thing it can do - putting that code in FLASH."