Yuav ua li cas cov raspberry pi emulator khoom ua haujlwm?
A Raspberry Pi emulator kit transforms the single-board computer into a multi-console gaming system by combining specific hardware components with emulation software that mimics classic gaming hardware. Cov txheej txheem ua haujlwm dhau los ntawm cov txheej txheem txawv - cov cuab yeej ua haujlwm sau lubnulation, uas txhais cov kev ua si qub ua si rau cov lus qhia PI tuaj yeem ua tiav.
Cov khoom siv feem ntau suav nrog Raspberry Pi Board nws tus kheej, micruld card ua ntej Retropie, cov khoom siv hluav taws xob, thiab ntau zaus nrog cov khoom txias. Thaum koj lub zog ntawm lub system, nws khau rau hauv emulationstation, cov duab graphical interface uas cia koj xauj thiab tso cov khoom ua si khaws cia ua ROM cov ntaub ntawv.
Qhov peb {- txheej archecture
Kev nkag siab tias cov khoom siv ua haujlwm no yuav tsum saib ntawm peb cov khaubncaws ua ke uas txhua tus tuav haujlwm tshwj xeeb.
Cov Khoom Kho Vajtse: Lub Hauv Paus
Hauv qab hauv qab qhov rooj ntawm lub cev raspberry pi board {model b los yog tus tshiab} A7 GHz, Phauj Nrog 2GB ntawm LPDR4 RAM. Lub PI 5 Ups tus ante nrog cortex -} A76 CORES ntawm 2.4 GHz thiab txhim kho cov duab txheej.
Cov khoom siv kho vajtse no vim tias emulation yog suav kim. Lub PI yuav tsum rau simulate cov cuab yeej sib txawv ntawm cov txheej txheem sib txawv hauv qhov tseeb- lub sijhawm. Ib qho kev ua si rau SuperSo, piv txwv li, siv 16 {{- me ntsis yuav ua li cas, ces muab cov txiaj ntsig los ntawm nws cov duab raj kab ntoo.
Cov videocore GPU nrhiav cov duab nraaj. Nyob rau PI 4, nws khiav ntawm 500 MHz, thaum lub PI 5 tus tshiab videocore vii GPU nce mus txog 800 MHz. Qhov GPU nrawm nrawm yog qhov tseem ceeb rau kev ua si du. Yog tsis muaj nws, CP CPU yuav tawm tsam kom tswj cov nqi ib txwm muaj, tshwj xeeb yog cov nintendo 64 lossis playstation.
Cia los ntawm micro Microd phaib, feem ntau yog 32 GB rau 128GB. Kev ua si ROMs (Cov ntawv luam digital ntawm cartridge cov ntaub ntawv) nyob ntawm no nrog lub operating system. Faster UHS - Kuv lossis UHS - II rated lub sijhawm thauj khoom thiab txo qis thaum lub sijhawm gameplay.
Software txheej: emulation pawg
Saum toj no cov khoom siv tau khiav hloov kho ntawm raspberry Pi OS (raws li Debian Linux). Lub teeb yuag yuag no muab lub hauv paus rau emulation software thaum tsis tshua muaj peev txheej siv nyiaj siv.
Cov khoom siv feem ntau siv Retropie, kev faib khoom software uas yuav tsum muaj txhua yam uas xav tau rau Retro Gaming. Retropie nws tus kheej tsis yog emulator - nws yog ib phau ntawm cov cuab yeej uas ua haujlwm ua ke. Ntawm nws cov tub ntxhais zaum retroarch, "Frontend" uas muab cov chaw sib koom ua ke rau ntau lub enulation cores.
Cov cores no yog cov emulators tiag tiag. Txhua tus tub ntxhais ua kom pom tseeb ib qho kev twv txiaj tshwj xeeb. Piv txwv li, SNES9X tub ntxhais Emulates Super Nintendo kho vajtse, thaum PCSx cov cuab yeej ua si ua si. Retroarch thauj cov kev tsim nyog raws li cov kev ua si uas koj xaiv, tom qab ntawd cov maub los tswj cov tswv yim thiab tswj lub suab / yees duab tawm.
Kev sib raug zoo ntawm cov khoom sib xyaw ua qhov no: emulationstation (cov ntawv qhia zaub mov koj pom) → {{{{{{{{{{{{{{{{{{{{{{{{{{{{{} → koj cov ntaub ntawv (LOM).
Thaum koj xaiv ib qho kev ua si, emulationstation qhia Retroarch uas tseem ceeb los thauj khoom thiab uas Rom cov ntawv tso. Retroarch pib qhov tseem ceeb, loads cov ntaub ntawv ua si, thiab pib txheej txheem emulation. Koj cov tswv yim txhawb tau txhais tau txhais los ntawm Retroarch lub tswv yim tawm mus rau hauv hom ntawv xav tau.
Interface txheej: ua rau nws siv tau
Emulationstation muab cov ntawv qhia kev pom. Nws yog scans koj cov lus qhia rom, qhia cov npe kev ua si sau npaj los ntawm console, thiab qhia lub thawv kos duab lossis cov screenshots (yog tias koj tau rub tawm metadata dhau ntawm nws cov scraping feature). Navigation siv gamepad lossis keyboard - tsis muaj nas.
Kev teeb tsa tshwm sim los ntawm cov neeg zes. Koj tuaj yeem hloov kho cov yeeb yaj kiab, sau tswj ib qho - kev ua si lossis ib} kev ua si, pab lav, lossis kev teeb tsa network. Tus hotkey system cia koj nkag mus rau cov kev xaiv nruab nrab {4 4 Kev ua si los ntawm nias lub khawm sib xyaw, feem ntau xaiv + Pib qhib cov ntawv qhia zaub mov Retroarch.
Qhov no txheej txheem tsim txhais tau tias koj tuaj yeem sib pauv ib qho khoom sib pauv ib leeg tsis tau tsim txhua yam. Xav tau ib qho nab txawv emulator? Nruab ib qho kev sib txawv. XAV TXIV TSHAJ NTAWD? Hloov cov emulationstation thaum khaws retroarch. Xav tau lub zog ntxiv? Hloov kho koj cov qauv PI thiab hloov koj daim npav micro micr.
Yuav ua li cas emulation ua tau tshwm sim tiag tiag
Thaum koj pib ua si, ntau cov txheej txheem tshwm sim hauv milliseconds. Cov emulator tseem ceeb ntawm cov ntaub ntawv LOM sau rau hauv kev nco, parses nws cov qauv kom nkag siab txog cov lus qhia kev ua si thiab cov khoom lag luam, tom qab ntawd pib ua haujlwm cov lus qhia.
{{{0} Kev txhais lus lub sijhawm yog qhov kev sib tw tseem ceeb. Tus thawj console's CPU tau qhia txog ib qho kev qhia sib txawv ntau dua li PI lub caj npab processor. Cov emulator yuav tsum txhais txhua cov lus qhia los ntawm cov kev qhia qub, xam seb nws yuav tsum ua li cas, tom qab ntawd ua tiav cov haujlwm sib npaug ntawm PI.
Qhov kev txhais no tsim siv nyiaj siv ua haujlwm. Qhov taw qhia yuav xav tau 10 lossis 20 caj npab qhia rau simulate yog. Muab cov lus qhia ntxiv no los ntawm ntau lab ntawm cov lus qhia ua tiav ib zaug thaum ua si, thiab koj pom vim li cas emulation xav tau siv zog ntau ua haujlwm.
Qee qhov kev pom zoo pab. Dynamic recompilation (dynarec) translation blocks ntawm tus thawj code rau hauv caj npab rau -}}}} ya, caching cov txiaj ntsig tau rau kev rov siv dua. Qhov no nrawm dua li txhais lus rau txhua tus. Zoo - Cov Cores zoo li PCSX Cov
Gratural emulation ua raws txoj kev ua tib zoo. Thawj cov consoles tau dedicated graphics chips nrog cov peev xwm tshwj xeeb {{}} sprite tuav, keeb kwm txheej, tshwj xeeb cuam tshuam. Cov emulator yuav tsum ua si cov software, tom qab ntawd muab cov txiaj ntsig los ntawm PI tus GPU siv OpenGL. Qhov no yog qhov twg GPU kev ua kom nrawm dua li tseem ceeb; Software rendering ib leeg tsis tuaj yeem tuav tau 60 FPS rau cov kev xav tau ntau dua.
Audio cov pib sib tw sib haum. Lub emulator simulates lub suab cim tus cwj pwm tus cwj pwm, tsim cov willforms uas phim cov khoom siv kho vajtse qub. Cov dej audio no ces txau los ntawm PI tus audio saysystem, txawm hais tias yog HDMI suab, lub mloog pob ntseg Jack, lossis Bluetooth rau cov neeg hais lus tsis zoo.
Ciaj ciam
Tsis yog txhua lub tshuab emulate zoo sib xws. Lub pi 4 leeg 8 {{4- me ntsis thiab 16-ntsis ntse-nes, taw, tus tub ua si txhua tus khiav ntawm qhov nrawm nrog qhov tseeb. Playstation 1 Kev ua si feem ntau ua haujlwm tau zoo, txawm hais tias qee lub npe pom qeeb qeeb thaum lub scenes nyuaj.
Nintendo 64 emulation hits kev ua yeeb yam phab ntsa. Lub kaw lus ntawd yog cov ntsiab lus tsis yooj yim rau kev coj losat kom raug txawm tias muaj lub zog loj. Lub PI 4 tuaj yeem khiav qee qhov N64 kev ua si ntawm kev ua si nrawm nrog txo cov chaw muaj tseeb, tab sis xav tau cov npe zoo li Rogue Squarron tseem ntov. PI 5 txoj kev hloov pauv tau pab ntawm no, nrog kev qhia ntawm N64 tau sib xyaw zoo dua, txawm tias nws tseem tsis zoo tag nrho.
Dreamcast emulation Qhia cog lus rau PI 5 siv Redream emulator. PlayStation 2, GameCube, thiab Wii nyob twj ywm ntau ntawm mus txog - Cov kab ke no tsuas yog dhau lawm rau PI lub peev xwm. Lawv cov multi-} processor architecture thiab cov duab ntse uas yuav tsum muaj lub tsev kho mob txawm tias PI 5 tsis tuaj yeem muab xwm yeem.
Raws li kev sim los ntawm Tom cov khoom siv kho vajtse, tus nqi thav duab tuaj yeem tso tawm tau nrog cov khoom ua si ua si ntawm PI 4, nrog kev sib ntaus sib tua ua si thaum khawm khawm. Tsis ntev los no cov qauv coj los ntawm PI 4 pom tau ua tau zoo nrog cov npe du, tshwj xeeb tshaj yog rau 2D thiab tsawg dua xav tau 3D kev ua si.
Lub pi 5 coj kev txhim kho ntsuas tau. Kev ntsuam xyuas ywj siab qhia txog PI 5 Kev tsim kho cov kev txhim kho zoo li Numa emulation tuaj yeem txhawb tau ntau dua 18%, txawm tias xws li kev hloov kho ntawm cov neeg siv cov kev teeb tsa.
TUS MIS QHOV KEV TXHAWB txhais lus System
Xws li cov txhawb nqa kev tsim nyog tshwj xeeb mloog vim tias nws tsis nkag siab. Thaum koj thawj zaug khau raj Retropie, nws thov kom koj los teeb tsa tus maub los ntawm nias txhua khawm- pob tw, pib / xaiv, thiab "Notkey Enable" khawm.
Qhov kev teeb tsa thawj zaug qhia koj lub cev tswj hwm rau EulationStStation cov ntawv qhia zaub mov system thiab tsim cov hauv paus ntsiab lus rau retroarch. Retroarch ces txiav Generates cov tswj hwm kev teeb tsa rau txhua tus tub ntxhais emulator raws li qhov profile ntawd.
Tab sis ntawm no yog qhov twg nws tau nthuav: sib txawv consoles muaj cov khawm sib txawv. Tus ntaus tus maub los muaj plaub lub ntsej muag khawm thiab ob lub xub pwg khawm. Tus maub los ua si ntxiv ntxiv ob lub xub pwg khawm thiab analog sticks. Ib tus meneresfer tsuas muaj peb lub ntsej muag khawm thaum pib.
Retroarch cov tswj hwm tsis txaus ntseeg txheej Maps koj cov maub los cov maub los khawm rau Annowing lub khawm rau Anyone qhov kev xav tau. Yog tias koj siv lub playstation Dualshock 4 nrog 16 khawm los ua si ib qho kev ua si nes tsis quav ntsej cov kev ua si yog tias koj tau siv lub xeev emulator zoo li txuag tau xeev lossis ceev-}}}}}}}}}}}}}}}}}}}}}}}}}}}}
Per - Kev Ua Si Rov Tau Ua Tau. Yog tias lub npe tshwj xeeb uas tsis txaus ntseeg nrog lub neej ntawd daim phiaj, koj tuaj yeem nkag mus rau hauv cov zaub mov retroarch thaum kev tswj hwm ntawm kev ua si. Cov kev hloov pauv cia li cia li.
USB controllers ua hauj lwm rau plug -}}- Ua si tom qab kev teeb tsa thawj zaug. Bluetooth controllers xav tau khub los ntawm Retropie's Bluetooth teeb zaub mov, uas taug kev los ntawm kev tshawb pom thiab kev sib txuas. Ib zaug ua khub, Bluetooth controllers rov txuas ntxiv rau khau raj.
Cia thiab Kev Tswj Xyuas Cov Ntaub Ntawv
MicroD daim npav qauv yog ncaj tab sis tseem ceeb kom nkag siab. Cov / khau raj muab faib muaj lub linux kernel thiab khau raj configuration cov ntaub ntawv. Lub ntsiab faib tuav cov kev ua haujlwm ua haujlwm, software Retropie, thiab koj cov ROMs.
LOM cov ntaub ntawv nyob hauv / Tsev / Petropie / Roms /, nrog subdirectories rau txhua kab ke- nees ntawm kev pib thiab qhia tawm txhua yam nws pom.
Tau txais ROMs mus rau PI tau tshwm sim ntau txoj hauv kev. Lub USB txoj kev yog qhov yooj yim tshaj plaws: Tsim cov nplaub tshev uas tau tsim Retropie ntawm Fat32-ntsaws nws thiab luam tawm cov ntawv tais ceev tseg rau hauv cov ntawv tais ceev tseg hauv koj lub khoos phis tawm. Ntsaws nws rov qab rau hauv pi, tos rau kev hloov pauv, thiab rov pib dua.
Network hloov chaw ua haujlwm ntawm samba (Windows cov ntaub ntawv sib qhia). Los ntawm lwm lub khoos phis tawm ntawm koj lub network, koj tuaj yeem nkag tau \\\\ Retropie thiab pom cov ROM carters ncaj qha. Luag thiab poob cov ntaub ntawv raws li xav tau, tom qab ntawd pib emulationstation los kho cov npe game.
Qee lub tshuab xav tau bios files - binary code los ntawm cov khoom siv tam sim no xav tau rau kev raug emulation. Playstation emulation, piv txwv li, xav tau PS1 BIOS. Cov ntaub ntawv no mus rau hauv / Tsev / PI / Retropie / BIOS /. Yog tsis muaj lawv, ntau qhov kev ua si yuav tsis thauj khoom.
Txuag cov xeev txawv txawv ntawm - kev ua si txuag. Hauv - kev ua si txuag tau raws nraim li lawv tau ua ntawm cov khoom siv ua ntej, khaws cia hauv ROM cov ntaub ntawv txuag. Txuag cov xeev yog emulator yam uas snapshot tag nrho cov kab ke lub xeev thaum txhua lub sijhawm. Koj tuaj yeem txuag thiab thauj cov no tam sim ntawd, txawm tias nyob hauv kev ua si uas tsis tau txuag kev ua haujlwm. Retroarch khw muag khoom no hauv / Tsev / PI / Retropie / Retroarch / xeev /.
Lub Zog thiab Thermal Kev Tswj Xyuas
Lub hwj chim xa khoom cuam tshuam rau kev ua tau zoo tshaj ntau tus paub. PI 4 yuav tsum tau 5V / 3A (15W) fais fab tuag; PI 5 xav tau 5V / 5A (25w) rau kev ua haujlwm ruaj khov, tshwj xeeb nrog kev xav tau emulation. Underpowering ua rau throttling- qhov system cia li txo moos ceev kom tiv thaiv kom tsis txhob muaj qhov tsis txaus ntseeg, ua rau muaj kev gameplay.
Lub PI tsis muaj lub zog khawm nyob rau hauv kev txiav txim ib txwm muaj. Plugging hauv lub zog hloov nws. Cov ntawv kaw cia kom zoo yuav tsum tau siv Eugulation cov ntawv qhia zaub mov "Wilddown System," uas ua tau ib qho kev kaw huv ua ntej txiav lub zog. Cias unplugging kev pheej hmoo PI kev pheej hmoo ua rau koj daim npav rho tawm.
Tshav kub ua ib qho kev ua haujlwm thaum lub sijhawm ua si txuas ntxiv. Lub PI 4 tsim kom muaj cua sov tseem ceeb hauv qab thauj, nrog kuaj ntsuas thermal thermal tuaj yeem tshwm sim tsis muaj cua txias. Cov ntaub ntawv nrog ua - hauv cov kiv cua lossis heatsinks tiv thaiv qhov no. Lub PI 5 khiav nrawm vim nws qhov kev ua tau zoo ntxiv, ua kom cov kev ua kom muaj kev xav tau kom muaj kev sib xws.
Overclocking thawb lub pi dhau nws Tshuag ceev rau kev ua tau zoo dua. Qhov no nce ob lub zog teeb tsa thiab cov khoom tawm cua sov. Cov kev xaiv tsis ntev los no rau SDRAM lub sijhawm ntawm PI 5 tiav 10-20% kev txhim kho ceev ntawm cov moos, nrog ceev kev overclocking ncav cuag mus txog 32% nce ntawm 3.2 GHz. Xws li kev hloov kho yuav tsum tau ua kom txias thiab muaj kev pheej hmoo ntawm qhov tsis muaj peev xwm.
Lwm Txoj Kev Platform Emulation
Thaum Retropie Dominates, xaiv tau muaj nrog cov tswv yim sib txawv. Daim ntawv thov rov qab ua ntej yuav siv nrog ntau dua kev siv tshuab tab sis tsis tshua customization. Lakka muaj lub teeb yuag, console - li kev ua kom siv nyiaj rhoelec raws li nws lub hauv paus. Batocera muab kev txhawb nqa platform dav heev thiab ua - hauv kev ua si streaming muaj peev xwm.
Tsis ntev los no Platform sib piv ntawm PI 5 Show Batocera kev sib tw muaj kev txhawb nqa nrog 8} {} Cov neeg uas ua ntawv txhawb nqa nrog kev ua si nrog kev sib tshuam. Txhua lub platform ua cov luam tawm sib txawv ntawm kev yooj yim thiab hloov tau.
Cov archamental zoo ib yam li zoo sib xws thoob plaws platforms {{}} Linux puag, Retroarch lub moj khaum, ntau yam emulator cores. Cov sib txawv dag nyob rau hauv interface tsim, suav nta, thiab kev teeb tsa txoj kev teeb tsa. Cov neeg siv nrhiav kev tswj hwm ntau dua li qhov kev xav tau rau Retropie, thaum cov neeg xav tau ntsaws - {} Ua si yooj yim yuav xum cov recalbox.
Thaum tej yam tsis ua haujlwm
Kev ua tau teeb meem feem ntau los ntawm qee qhov chaw. Undermowed cov khoom siv ua rau kev sib tsoo lossis qeeb. Qeeb micro micro micro micrent tsim stuttering thaum lub nra hnyav. Overheating triggers throtling uas ua rau pom tias yog cov ncej qaj.
Yog tias ib qho kev ua si tshwj xeeb yuav tsis thauj khoom, tsis ncaj ncees lawm ROM hom ntawv feem ntau yog ua txhaum. Txawv emulator cores kev txhawb nqa cov ntaub ntawv sib txawv. PlayStation Games yuav nyob rau hauv .bin / .cue, .Chd tawm tswv yim {} Tsis muaj txhua tus cores nyeem txhua hom ntawv. Txheeb xyuas cov tub ntxhais cov ntaub ntawv qhia txog qhov ua tau nws xav tau.
Qee qhov kev ua si xav tau cov corulator tshwj xeeb. Neo games xav tau ob qho tib si game rom thiab Neo geo bios ntawv ua haujlwm. Arcade roms yuav tsum phim lub txiv neej emulator
Cov teeb meem tswj cov teeb meem feem ntau trace rau lub hotey kev teeb tsa. Yog tias cov nyees khawm zoo li tsis teb chaws, nws nquag vim tias tus retroorch enable khawm uas nws tau tos rau emulator cov lus txib es tsis txhob nkag mus rau qhov kev ua si.
Cov Lus Nquag Nug
Kuv puas tuaj yeem siv cov qauv raspberry pi rau emulation?
Thaum twg ib qho PI thev naus laus zis, PI 4 nrog tsawg kawg yog 2GB RAM yog cov tswv yim yam tsawg kawg nkaus nrog kev ua tau zoo nrog cov kev ua haujlwm zoo. Cov qauv ua ntej kev tawm tsam nrog txhua yam dhau ntawm 8-ntsis consoles. Lub Pi Xoom yog underpowered rau xis nyob emulation ntawm cov tshuab dhau ntawm NES / Game Boy Era.
Kuv puas xav tau thawj kev ua si cartridges siv emulator cov khoom siv raug cai?
Kev cai lij choj txwv nyob ib ncig ntawm Romary los ntawm kev txiav txim. Txoj kev nyab xeeb ntau yog tsuas yog siv kev ua si uas koj tus kheej cov ntawv luam ntawm, txawm hais tias txoj kev ua yeeb yam thiab kev paub meej kev sib txawv ntawm thaj av. Retropie suav nrog tsis muaj cov ntsiab lus txwv- Koj yuav tsum muab koj cov ntaub ntawv ua si.
Kuv puas tuaj yeem ntxiv kev ua si tom qab pib teeb tsa?
Yog lawm, ntxiv cov ROMs yog ncaj ncaj siv siv USB hloov lossis network cov ntaub ntawv sib qhia. Muab cov ntaub ntawv sau rau hauv cov ntawv sau cia kom tsim nyog nyob rau hauv / hauv tsev / petropie / Roms /, tom qab ntawd pib emulationstation los kho cov npe game.
Kuv xav tau ntau npaum li cas?
25GB microSD daim npav tuav pua pua ntawm 8- ntsis thiab 16-ntsis ua si. PlayStation thiab N64 Games Ua qhov chaw ntau dua li 500Mb rau PS1 kev ua si, 10-50MB rau N64 lub npe. Ib daim npav 64GB muab chav nyob zoo rau chav tsev muaj ntau thoob plaws ntau lub nruab nrab.
Saib ntawm lub kaw lus tiav
Cov muaj kuab heev ntawm Raspberry Pi emulator cov khoom dag nyob rau hauv li cas cov khoom sib xyaw ua ke yooj yim sib xyaw ua ke rau hauv lub peev xwm retro kev daws kev twv txiaj. PI lub caj npab processor tsis tsim rau emulation, tsis tau los ntawm ntse kev ua kom zoo, nws rov ua kom zoo dua kev ua haujlwm ntawm cov tshuab uas tau siv tag nrho cov archentic.
Cov qauv modular txhais tau tias cov kab ke txhim kho nce siab ntxiv. Zoo emulator cores tshwm tsis tu ncua, ntxiv cov tseeb lossis kev ua tau zoo. Firmware hloov kho tshiab txhim kho PI lub peev xwm. Koj tuaj yeem hloov kho ib tus neeg - Lub cim micrterd dua, muaj ntau cov qauv PI nrawm dua, tsis muaj pib dua.
Rau ib tug neeg xav kom nkag siab ntau dua li siv cov khoom siv no, qhov tseem ceeb ntawm kev pom ntawm cov khaubncaws sab nraud ua ke, txhua qhov kev txhais ntawm cov neeg sawv cev sib txawv ntawm tib yam. Qhov kev ua si xav tias nws tau khiav ntawm nws cov khoom siv qub, tab sis nws tau ua tiag khiav ntawm software uas simulates hais tias kho vajtse, uas nws tus kheej sau ntawm kev sib txawv ntawm kho vajtse. Lub zog raspberry pi cov zog txaus, sib xyaw ua ke nrog qhib-}}}}} Cov lus txhais no nrawm txaus rau tiag {3} kev twv txiaj.
Qhov kev sib xyaw ua ke ntawm cov khoom ntiag tug thiab paub tab tau piav qhia yog vim li cas "nyuam qhuav tau txais PI" tau dhau los ua cov lus qhia rau Retro Gaming. Thaum tsis zoo tshaj plaws -}}}} Lub peev xwm zoo tshaj plaws ntawm tus nqi, kev ua tau zoo, thiab kev ua tau zoo rau kev khaws cia thiab txaus siab rau kev ua si classic.