JOYTemplate for Footer group ” ÿÿh�ËX�S%¶k…òI”z ¶kÐ pÐhlÂìŠI” Y÷%Á³Ðz ¶kZ-–K¥Òi´Z-–KÁ Nä"Õ¦I…` ¶{x„ R< Nä"Õ¦I…` ¶{x„ R<Lï$ЦI”z ¶yx ULï$ЦI”z ¶xx ULï$ЦI”z ¶x ULï$ЦI”z ¶~x ULï$ЦI”z ¶}x ULï$ЦI”z ¶|x ULï$ЦI”z ¶sx ULï$ЦI”z ¶rx UModern €+¶¹+Yº²‚»»»»»"»›Ù¼»»KºÛº¹¼»í»[XÛ¹šš™:†Ñ©ª©˜Úº˜R¹½j–’¹‰ˆ¹™Ë}×[Y™qË«‹Ë»»»»ÝÝÝÝÝ"wD“d›9›r›£¹9š9ºšÌÜ»­îÛ›‰Ì·š›®Y–g»»»»»»»»»»»»»»»»»»»»»»»»»»»»»»»»»»»»»»»»»»»»»»»»Í»»»´Úº™»«Û»¨‰‰ˆ©š¨¸™™»—‹˜¸‰ëÉ«¬�»Û»»ºº½œÊ˜‰¸Ù©©½™Û«ÛÙ˜Œ€ x€Script 1: 0x„ R< ÈИ 0MONITORPROGRAMx€ x€Script 1: 0x„ R< È &KPage===å :(c)copyright1989byGeoffBuckeridgeð€€ x€Script 1: 0x„ R< È€˜ ˆMONITORPROGRAM(cont)x€ x€Script 1: 0x„ R< È &KPage===å :(c)copyright1989byGeoffBuckeridge€€ x€Script 1: 0x„ R< È TheMONITORprogramdescribedhereiswrittenin'C'andenablesyoutolookat  any'block'ofmemorywhereveritis'paged'intothesystem.Itisaread-only  H1monitor,unliketheoneIwroteforthe'April1988editionofComputingwith ! theAmstradPCW'.ThisonewaswritteninBASICbutallowedyoutoaltertheZcontentsofanymemorylocation.  lUForthoseofyouwhoareunabletoseeacopyofthismagazine,thenext  :#threeparagraphsexplain'memorypagingandblockswitching.Ialsoreferyou�to'TheAmstradCP/MPlusbyDavidPowysLybbeandAndrewR.M.Clarke.  5TheZ80,asweknow,isonlycapableofaddressingupto64Kofmemory,and ¥ŽyetwealsoknowthatthePCWcanhaveeither256Kor512Kfittedas  standard.So,howisallthisextramemoryaccessed,andhowcanwestudyitscontentsorchangeit.  qZThesecretliesintheterm"MemoryPaging".InthePCW,the64Kaddress rangeisdividedintofour16Kpages.The256Kor512Kofphysicalmemoryis  F/alsosplitinto16Kchunks,knownasblocks."MemoryPaging"then,describesatheabilitytoswitchdifferentmemoryblocksintodifferentaddresspages.  Say,forexample,atpower-onblocks0,1,2&3areswitchedintopages0,1, …n2&3,andlateron,youwanttouseblock14.Itissimplyamatterof  3swappingoneofyourpreviouslyselectedblocksfornumber14.Forinstance, ! youcouldnowhaveblocks0,1,14&3selected.Block14thenreplacesBlock  T=2,appearstobeinaddressrange8000-BFFF(Hex),andcanbereadeither  fromamachinecodeprogram,orusingtheBASICPEEKstatement.Inpractice,  G0onthePCWthetoppageofmemory,page3addressingC000-FFFF(Hex),will >'alwaysselectblock7.ThiscommonRAMareacanbeusedtostoreprograms�in,sothatyouwillalwaysknowwheretofindthemagain.d x€Script 1: 0x„ R< È   �†ToinvoketheMONITOR,simplytypeMONITORattheCP/MpromptandtheÌinstructionsaredisplayed.