Avr asm label*2

Question

Hi i am new in avr asm programming,in the example below, i have few questions:

1) Is it label: 8 bit or 16bit long?

2) Why multiplication label with 2 is needed?

3) Instruction LPM is placing their result in register R0? If so, what does that have to do with Z?

4) Can you explaine the quoted text from the provided link:

"If the address is not multiplied by two and label is at byte address 0x60 (word address 0x30), Z will point at the code stored there. I hope this clarified the addressing problem. Other versions are"

ldi ZL, low(2*label)
ldi ZH, high(2*label)

label:
.db "Hello world", 0
lpm

Thanks.

Answer 1

1. Label is 16 bits.
2. Because the assembler is using word addresses, but LPM needs byte address. Note that not all assemblers do this, notably gas that's used by avr-gcc, doesn't. Then you don't need the multiplication.
3. Yes, the no-operands version of LPM automatically loads into R0, and it takes the address from Z. See the instruction set reference.
4. That wasn't too clear LOL, but see #2, above.