单片机原理及应用--第4章 80c51单片机汇编语言程序设计

CHAPTER4PROGRAMDESIGNOFASSEMBLELANGUAGE主讲教师黄英CONTENTS41INTRODUCTIONOFASSEMBLELANGUAGE2411FEATURES2412FORMAT242BASICSTRUCTURES2421SEQUENTIALPROGRAM2422BRANCHINGPROGRAM34221SINGLEBRANCHINGPROGRAM34222MULTIBRANCHINGPROGRAM111BYUSINGSOMECJNEINSTRUCTIONS112BYUSING“ADDRESSTABLE”133BYUSING“JUMPINSTRUCTIONTABLE”154BYUSINGSTACKOPERATION18423CIRCULARSTRUCTURE2343DELAYTIMEPROGRAM24431SINGLECYCLEDELAYTIMEPROGRAM24432LONGDELAYTIMEPROGRAM（MULTICYCLE）25433ADJUSTINGDELAYTIMERANGE25434GETDIFFERENTTIMINGWITHBASICDELAYPROGRAM2544PSEUDOINSTRUCTION2545HOWTOEDITANDASSEMBLETHESOURCEPROGRAM2541INTRODUCTIONOFASSEMBLELANGUAGE411FEATURES1PRODUCESTHEOPTIMIZEDPROGRAM2PROGRAMMERMUSTBEFAMILIARWITHHARDWARE3MANAGEANDCONTROLHARDWAREDIRECTLY4NOTUNIVERSAL,CANTBETRANSPLANTED412FORMAT（DETAILEDINFORMATIONP77）42BASICSTRUCTURES3TYPESSEQUENTIALSTRUCTUREBRANCHINGSTRUCTURECIRCULARSTRUCTURE421SEQUENTIALPROGRAMFOREXAMPLE3BYTEUNSIGNEDCONSTANTSADDITION422BRANCHINGPROGRAM4221SINGLEBRANCHINGPROGRAMUSINGJUMPINSTRUCTIONSP6768JZ,JNZ,CJNE,DJNZ（条件转移指令）P7374JC,JNC,JB,JNB,JBC（位控制转移指令）ASSUMEDTHAT50H52HCELLSOFINTERNALRAMHAVETHREEAUGENDSRESPECTIVELY（BEGINNINGWITHHIGHBYTES）,53H55HCELLSOFINTERNALRAMHAVETHREEADDENDSRESPECTIVELY（BEGINNINGWITHHIGHBYTES）REQUIREMENTDESIGNAPROGRAMTOPUTTHEADDITIONRESULTINTO50H52HCELLS（BEGINNINGWITHHIGHBYTES）,ANDTHECARRYBITINTO20HBITOFBITADDRESSABLEAREAMOVR0,52HMOVR1,55HMOVA,R0ADDA,R1MOVR0,ADECR0DECR1MOVA,R0ADDCA,R1MOVR0,ADECR0（50H/51H/52H）11H/22H/33HDECR1（53H/54H/55H）77H/88H/99HMOVA,R0ADDCA,R1112233HMOVR0,A778899HCLRAADDCA,00HMOVR0,20HMOVR0,AFOREXAMPLECOMPARETHEVALUESSTARTCLRCCLEARTHECARRYBITMOVDPTR,ST1SETTHEDATAPOINTERMOVXA,DPTRMOVR2,APUTTHE1STCONSTANTINTOR2INCDPTRMOVXA,DPTRPUTTHE2STCONSTANTINTOASUBBA,R2AAR22ST1STJNCBIG1IFNOCARRY,THENTHE2STCONSTANTISBIGGERXCHA,R2ELSE1STCONSTANTISBIGGER,ANDPUTINTOABIG0INCDPTRLETDPTRPOINTSTOTHERESULTCELLMOVXDPTR,ASAVETHEBIGGERCONSTANTRETBIG1MOVXA,DPTRPUTTHE2STCONSTANTINTOASJMPBIG04222MULTIBRANCHINGPROGRAMINSTRUCTIONSETHASNOMULTIBRANCHINGINSTRUCTION4METHODSTOREALIZEMULTIBRANCHING1BYUSINGSOMECJNEINSTRUCTIONS2BYUSING“ADDRESSTABLE”3BYUSING“JUMPINSTRUCTIONTABLE”4BYUSINGSTACKOPERATION1BYUSINGSOMECJNEINSTRUCTIONSCJNEA,DATA,RELPUTTHEBRANCHINGNUMBERINTOAFOREXAMPLETEMPERATURECONTROLSYSTEMCJNEA,55H,LOOP1IFTAT55（UPPERVALUELIMIT），THENJUMPTOLOOP1AJMPFHTAT55，JUMPTOMAINPROGRAMFH（返回）LOOP1JNCJWIFCY0，TAT55,THENJUMPTOJW（降温）CJNEA,54H,LOOP2IFTAT54（LOWERVALUELIMIT），THENJUMPTOLOOP2AJMPFHTAT54，JUMPTOMAINPROGRAM（FH）LOOP2JCSWIFCY1，TAT55,THENEXECUTESTHETEMPERATUREDOWNPROCESSINGSUBPROGRAM（JW）IFTA（R1SAVESHIGH8BITADDRESS）ANLA,0FHFETCHLOW4BITFROMHIGHADDRESS,ANDCLEARHIGH4BITANLP2,0F0HFETCHHIGH4BITFROMP2PORT,ANDCLEARLOW4BITOFP2ORLP2,ANOTCHANGEHIGH4BITOFP2,ANDSENDLOW4BITOFP2MOVXA,R0FETCHDATAFROMEXTERNALRAM（4KB）TOA（R0SAVESLOW8BITADDRESS）SJMPDONESTOPBR3MOVDPL,R003PUTLOW8BITADDRESSOFEXTERNALRAMTODPLMOVDPH,R1PUTHIGH8BITADDRESSOFEXTERNALRAMTODPHMOVXA,DPTRFETCHDATAFROMEXTERNALRAM（64KB）TOADONESJMPSTOP3BYUSING“JUMPINSTRUCTIONTABLE”FOREXAMPLER300,01,02,03,MOVA,R3PUTTHEBRANCHINGNUMBERINTOARLAABRANCHINGNUMBER2MOVDPTR,BRTABLETDPTRPOINTTOBASEADDRESSOFOFFSETTABLEJMPADPTRJUMPTOTHECORRESPONDINGSUBROUTINE,PCADPTRBRTABAJMPROUT0JUMPTOROUT0AJMPROUT1JUMPTOROUT1AJMPROUT2JUMPTOROUT2AJMPROUT3JUMPTOROUT3AJMPROUTNJUMPTOROUTNWHY“RLA”WHENR300,NEEDJUMPTOBRTAB0,SOA00,WHENR301,NEEDJUMPTOBRTAB2,SOA02,WHENR302,NEEDJUMPTOBRTAB4,SOA04,WHENR303,NEEDJUMPTOBRTAB6,SOA06ASSUMEDTHATTHEREAREFOURBRANCHINGPROGRAMS,WHICHFUNCTIONISTOFETCHDATAFROMINTERNALRAM,EXTERNALRAM（LOWER256B）,EXTERNALRAM（4KB）,ANDEXTERNALRAM64KBRESPECTIVELYTOAR0SAVESLOW8BITADDRESS,R1SAVESHIGH8BITADDRESS,R3SAVESBRANCHINGNUMBERBRTABDENOTESTHEBASEADDRESSOFOFFSETTABLEBR0_BRTABBR3_BRTABDENOTEOFFSETREQUIREMENTDESIGNAPROGRAMTOREALIZEMULTIBRANCHINGASSUMEDTHATR3SAVESBRANCHINGNUMBERBRTABDENOTESTHEBASEADDRESSOFJUMPINSTRUCTIONTABLEREQUIREMENTDESIGNAPROGRAMTOREALIZEMULTIBRANCHINGOFFSETTABLE（OFFSETVALUEBR0/BR1/BR2/BR3BRTAB）JUMPINSTRUCTIONTABLE4BYUSINGSTACKOPERATIONSTEPS（1）PUTTHE16BITADDRESSINTOSTACK（2）USINGRETINSTRUCTIONTOGETPCVALUEFROMSTACKFOREXAMPLER300,01,02,03MOVDPTR,BRTABLETDPTRPOINTTOBASEADDRESSOFOFFSETTABLEMOVA,R3PUTTHEBRANCHINGNUMBERINTOARLAABRANCHINGNUMBER2MOVR1,AR12R3INCAA2R31MOVCA,ADPTRFETCHLOW8BITADDRESSTOAPUSHACCANDPUTLOW8BITADDRESSINTOSTACKMOVA,R1MOVCA,ADPTRFETCHHIGH8BITADDRESSTOAPUSHACCANDPUTITINTOSTACKRETSETPCVALUEFROMSTACKGETHIGH8BITADDRESSFIRST,ANDTHENLOW8BITADDRESSBRTABDWBR016BITADDRESSOFBRANCHINGSUBROUTINE0DWBR116BITADDRESSOFBRANCHINGSUBROUTINE1DWBR216BITADDRESSOFBRANCHINGSUBROUTINE2DWBR316BITADDRESSOFBRANCHINGSUBROUTINE3DWBRN16BITADDRESSOFBRANCHINGSUBROUTINENNOTEBRTAB3000H16BITADDRESSR3R1RLAINCA3000HIGH8BITADDRESS3001LOW8BITADDRESSBR00013002HIGH8BITADDRESS3003LOW8BITADDRESSBR11233004HIGH8BITADDRESS3005LOW8BITADDRESSBR22453006HIGH8BITADDRESS3007LOW8BITADDRESSBR3367RETPC158SP,SPSP1PC70SP,SPSP1PUSHDIRECTSPSP1,（SP）（DIRECT）SONEEDTOPUSHLOW8BITADDRESSFIRST,ANDTHENPUSHHIGH8BITADDRESSATLAST423CIRCULARSTRUCTUREMETHODUSINGCONDITIONALJUMPINSTRUCTIONSFOREXAMPLEMOVR2,0FFHSETTHEINITIALVALUEOFTHELENGTHCOUNTERMOVR0,3FHSETTHEINITIALVALUEOFTHESTRINGPOINTERLOOPINCR2R200H,01H,INCR0R040H,41H,CJNER0,0DH,LOOPRETASSUMEDTHATR3SAVESBRANCHINGNUMBERBRTABDENOTESTHEBASEADDRESSOFJUMPINSTRUCTIONTABLEREQUIREMENTDESIGNAPROGRAMTOREALIZEMULTIBRANCHINGASSUMEDTHATTHEREISACHARACTERSTRINGTHATADOPTS“ENTER”SYMBOLASTHEENDINGFLAGTHISSTRINGISSAVEDINTHEINTERNALRAMBEGINNINGWITH40HCELLREQUIREMENTDESIGNAPROGRAMTOGETTHELENGTHOFTHISSTRING16BITADDRESSTABLEPAYATTENTIONTOTHEOPERATIONOFDW43DELAYTIMEPROGRAM431SINGLECYCLEDELAYTIMEPROGRAMMOVR5,TIME1LOOPNOP1NOP1DJNZR5,LOOP2IFFOSC6MHZ,THENMACHINECYCLETMSOTOTALDELAYTIMETMAX1（112）2USTIMETIME00HFFH,0255,CYCLES265TIMES1（112）2US256120482049US432LONGDELAYTIMEPROGRAM（MULTICYCLE）MOVR5,TIME11LOOP2MOVR4,TIME21LOOP1NOP1NOP1DJNZR4,LOOP12DJNZR5,LOOP22RET2IFFOSC6MHZ,THENTOTALDELAYTIMETMAXTMAX1（1（112）2562）256）2）2US1525828525829US433ADJUSTINGDELAYTIMERANGEBYADDINGORDELETINGINSTRUCTIONSTHATDONTAFFECTPROGRAMFUNCTIONMOVR0,TIME1LOOPADDA,R11INCDPTR2DJNZR0,LOOP2I