ref: 8003084cd54e4365cb0bc4d7cfbcac04a3385e32
dir: /home/serial.asm/
Serial:: ; The serial interrupt. push af push bc push de push hl ldh a, [hMobileReceive] and a jr nz, .mobile ld a, [wPrinterConnectionOpen] bit 0, a jr nz, .printer ldh a, [hSerialConnectionStatus] inc a ; is it equal to CONNECTION_NOT_ESTABLISHED? jr z, .establish_connection ldh a, [rSB] ldh [hSerialReceive], a ldh a, [hSerialSend] ldh [rSB], a ldh a, [hSerialConnectionStatus] cp USING_INTERNAL_CLOCK jr z, .player2 ld a, (0 << rSC_ON) | (0 << rSC_CLOCK) ldh [rSC], a ld a, (1 << rSC_ON) | (0 << rSC_CLOCK) ldh [rSC], a jr .player2 .mobile call MobileReceive jr .end .printer call PrinterReceive jr .end .establish_connection ldh a, [rSB] cp USING_EXTERNAL_CLOCK jr z, .player1 cp USING_INTERNAL_CLOCK jr nz, .player2 .player1 ldh [hSerialReceive], a ldh [hSerialConnectionStatus], a cp USING_INTERNAL_CLOCK jr z, ._player2 xor a ldh [rSB], a ld a, 3 ldh [rDIV], a .wait_bit_7 ldh a, [rDIV] bit 7, a jr nz, .wait_bit_7 ld a, (0 << rSC_ON) | (0 << rSC_CLOCK) ldh [rSC], a ld a, (1 << rSC_ON) | (0 << rSC_CLOCK) ldh [rSC], a jr .player2 ._player2 xor a ldh [rSB], a .player2 ld a, TRUE ldh [hSerialReceivedNewData], a ld a, SERIAL_NO_DATA_BYTE ldh [hSerialSend], a .end pop hl pop de pop bc pop af reti Serial_ExchangeBytes:: ld a, $1 ldh [hSerialIgnoringInitialData], a .loop ld a, [hl] ldh [hSerialSend], a call Serial_ExchangeByte push bc ld b, a inc hl ld a, $30 .wait dec a jr nz, .wait ldh a, [hSerialIgnoringInitialData] and a ld a, b pop bc jr z, .load dec hl cp SERIAL_PREAMBLE_BYTE jr nz, .loop xor a ldh [hSerialIgnoringInitialData], a jr .loop .load ld [de], a inc de dec bc ld a, b or c jr nz, .loop ret Serial_ExchangeByte:: .loop xor a ldh [hSerialReceivedNewData], a ldh a, [hSerialConnectionStatus] cp USING_INTERNAL_CLOCK jr nz, .not_player_2 ld a, (0 << rSC_ON) | (1 << rSC_CLOCK) ldh [rSC], a ld a, (1 << rSC_ON) | (1 << rSC_CLOCK) ldh [rSC], a .not_player_2 .loop2 ldh a, [hSerialReceivedNewData] and a jr nz, .reset_ffca ldh a, [hSerialConnectionStatus] cp USING_EXTERNAL_CLOCK jr nz, .not_player_1_or_wLinkTimeoutFrames_zero call CheckwLinkTimeoutFramesNonzero jr z, .not_player_1_or_wLinkTimeoutFrames_zero call .delay_15_cycles push hl ld hl, wLinkTimeoutFrames + 1 inc [hl] jr nz, .no_rollover_up dec hl inc [hl] .no_rollover_up pop hl call CheckwLinkTimeoutFramesNonzero jr nz, .loop2 jp SerialDisconnected .not_player_1_or_wLinkTimeoutFrames_zero ldh a, [rIE] and (1 << SERIAL) | (1 << TIMER) | (1 << LCD_STAT) | (1 << VBLANK) cp 1 << SERIAL jr nz, .loop2 ld a, [wcf5d] dec a ld [wcf5d], a jr nz, .loop2 ld a, [wcf5d + 1] dec a ld [wcf5d + 1], a jr nz, .loop2 ldh a, [hSerialConnectionStatus] cp USING_EXTERNAL_CLOCK jr z, .reset_ffca ld a, 255 .delay_255_cycles dec a jr nz, .delay_255_cycles .reset_ffca xor a ldh [hSerialReceivedNewData], a ldh a, [rIE] and (1 << SERIAL) | (1 << TIMER) | (1 << LCD_STAT) | (1 << VBLANK) sub 1 << SERIAL jr nz, .rIE_not_equal_8 ; LOW($5000) ld [wcf5d], a ld a, HIGH($5000) ld [wcf5d + 1], a .rIE_not_equal_8 ldh a, [hSerialReceive] cp SERIAL_NO_DATA_BYTE ret nz call CheckwLinkTimeoutFramesNonzero jr z, .linkTimeoutFrames_zero push hl ld hl, wLinkTimeoutFrames + 1 ld a, [hl] dec a ld [hld], a inc a jr nz, .no_rollover dec [hl] .no_rollover pop hl call CheckwLinkTimeoutFramesNonzero jr z, SerialDisconnected .linkTimeoutFrames_zero ldh a, [rIE] and (1 << SERIAL) | (1 << TIMER) | (1 << LCD_STAT) | (1 << VBLANK) cp 1 << SERIAL ld a, SERIAL_NO_DATA_BYTE ret z ld a, [hl] ldh [hSerialSend], a call DelayFrame jp .loop .delay_15_cycles ld a, 15 .delay_cycles dec a jr nz, .delay_cycles ret CheckwLinkTimeoutFramesNonzero:: push hl ld hl, wLinkTimeoutFrames ld a, [hli] or [hl] pop hl ret SerialDisconnected:: dec a ; a is always 0 when this is called ld [wLinkTimeoutFrames], a ld [wLinkTimeoutFrames + 1], a ret ; This is used to exchange the button press and selected menu item on the link menu. ; The data is sent thrice and read twice to increase reliability. Serial_ExchangeLinkMenuSelection:: ld hl, wPlayerLinkAction ld de, wOtherPlayerLinkMode ld c, 2 ld a, TRUE ldh [hSerialIgnoringInitialData], a .asm_847 call DelayFrame ld a, [hl] ldh [hSerialSend], a call Serial_ExchangeByte ld b, a inc hl ldh a, [hSerialIgnoringInitialData] and a ld a, FALSE ldh [hSerialIgnoringInitialData], a jr nz, .asm_847 ld a, b ld [de], a inc de dec c jr nz, .asm_847 ret Serial_PrintWaitingTextAndSyncAndExchangeNybble:: call LoadTilemapToTempTilemap callfar PlaceWaitingText call WaitLinkTransfer jp SafeLoadTempTilemapToTilemap Serial_SyncAndExchangeNybble:: call LoadTilemapToTempTilemap callfar PlaceWaitingText jp WaitLinkTransfer ; One "giant" leap for machinekind WaitLinkTransfer:: ld a, $ff ld [wOtherPlayerLinkAction], a .loop call LinkTransfer call DelayFrame call CheckwLinkTimeoutFramesNonzero jr z, .check push hl ld hl, wLinkTimeoutFrames + 1 dec [hl] jr nz, .skip dec hl dec [hl] jr nz, .skip ; We might be disconnected pop hl xor a jp SerialDisconnected .skip pop hl .check ld a, [wOtherPlayerLinkAction] inc a jr z, .loop ld b, 10 .receive call DelayFrame call LinkTransfer dec b jr nz, .receive ld b, 10 .acknowledge call DelayFrame call LinkDataReceived dec b jr nz, .acknowledge ld a, [wOtherPlayerLinkAction] ld [wOtherPlayerLinkMode], a ret LinkTransfer:: push bc ld b, SERIAL_TIMECAPSULE ld a, [wLinkMode] cp LINK_TIMECAPSULE jr z, .got_high_nybble ld b, SERIAL_TIMECAPSULE jr c, .got_high_nybble cp LINK_TRADECENTER ld b, SERIAL_TRADECENTER jr z, .got_high_nybble ld b, SERIAL_BATTLE .got_high_nybble call .Receive ld a, [wPlayerLinkAction] add b ldh [hSerialSend], a ldh a, [hSerialConnectionStatus] cp USING_INTERNAL_CLOCK jr nz, .player_1 ld a, (0 << rSC_ON) | (1 << rSC_CLOCK) ldh [rSC], a ld a, (1 << rSC_ON) | (1 << rSC_CLOCK) ldh [rSC], a .player_1 call .Receive pop bc ret .Receive: ldh a, [hSerialReceive] ld [wOtherPlayerLinkMode], a and $f0 cp b ret nz xor a ldh [hSerialReceive], a ld a, [wOtherPlayerLinkMode] and $f ld [wOtherPlayerLinkAction], a ret LinkDataReceived:: ; Let the other system know that the data has been received. xor a ldh [hSerialSend], a ldh a, [hSerialConnectionStatus] cp USING_INTERNAL_CLOCK ret nz ld a, (0 << rSC_ON) | (1 << rSC_CLOCK) ldh [rSC], a ld a, (1 << rSC_ON) | (1 << rSC_CLOCK) ldh [rSC], a ret Function919:: ; unreferenced ld a, [wLinkMode] and a ret nz ld a, USING_INTERNAL_CLOCK ldh [rSB], a xor a ldh [hSerialReceive], a ld a, (0 << rSC_ON) | (0 << rSC_CLOCK) ldh [rSC], a ld a, (1 << rSC_ON) | (0 << rSC_CLOCK) ldh [rSC], a ret