Gameboy Transfer SGB Packets

;I don't know if this is the best or most optimized way to transfer SGB packets; it just works

sendSGBPacket:
    ld b, 16            ;Number of bytes to send
    ld c, 1             ;Number to AND with
    ld hl, PAL          ;Address of the packet
    ld de, $FF00        ;Address of the joypad register
    ld a, $00           ;Load zero into A
    ld [de], a          ;Set P14 and P15 to low
    ld a, $30           ;Load 0x30 into A
    ld [de], a          ;Set P14 and P15 to high
.sendPacketLoop:
    ld a, [hl]          ;Load a byte into A
    and c               ;AND it with C
    jp nz, .sendZero    ;If the bit is zero, send a zero
.sendOne:
    ld a, $20           ;Load 0x20 into A
    ld [de], a          ;Set P15 to high
    jp .afterBit        ;Don't write a zero
.sendZero:
    ld a, $10           ;Load 0x10 into A
    ld [de], a          ;Set P14 to high
.afterBit:
    ld a, c             ;Load C into A
    cp $80              ;Compare it with 0x80
    jp z, .resetAND     ;Reset the AND value if it is true
    sla c               ;If not, shift C left by one
    jp .skipResetAND    ;Don't reset the AND value
.resetAND:
    ld c, $01           ;Load 0x01 into C
    inc hl              ;Point to the next packet byte
    dec b               ;Decrement the loop counter
    ld a, b             ;Load B into A
    cp $00              ;Compare it with 0x00
    jp z, .doneSending  ;B is zero, all bytes are transferred, done transferring
.skipResetAND:
    ld a, $30           ;Load 0x30 into A
    ld [de], a          ;Set P14 and P15 to high
    ld a, [hl]          ;Load a packet byte into A
    jp .sendPacketLoop  ;Loop to transfer
.doneSending:
    ld a, $30           ;Load 0x30 into A
    ld [de], a          ;Set P14 and P15 to high
    ld a, $20           ;Load 0x20 into A
    ld [de], a          ;Set P15 to high
    ret