OUTI - Z80 instruction reference

outiOutput and increment 
Decrements B, writes the byte at (HL) to the port addressed by BC, then increments HL.
2 bytes · 16 cycles
SZHP/VNC ?●??1?
● set from the result
1 always 1
? undefined afterwards
Forms  outi  
B is decremented. A byte from the memory location pointed to by HL is written to the port at the 16-bit address contained in the BC register pair. Then HL is incremented. Note that the carry flag may be affected, contrary to documentation. Read More
         .org 0x8000
        ld hl, source
        ld b, 2
        ld c, 1
        outi
        halt
source: .byte 42, 7