John,
The LDI instruction moves the value from IM(65535), zero extends it, and stores it into REG1. This
instruction is one form of MOV (the MOV pseudo op uses LDI when the source data is an immediate
value).
Definition:
LDI REG1, IM(65535)
Operation:
REG1 = IM(65535)
Example:
ldi r1, 10 // Load 10 into r1
ldi r1, #10 // Load 10 into r1
ldi r1, 0b10 + 020/2 // Load 10 into r1