计算机组成原理与汇编课件第6章子程序结构

1.过程定义伪操作过程名PROCNEAR(FAR)...过程名ENDP（1）NEAR属性：调用程序和子程序在同一代码段中（段内调用）（2）FAR属性：调用程序和子程序不在同一代码段中（段间调用）codesegmentsegxsubtsegmentproc……retendp……subt……farmainproc……call……retendpfarsubr1subtcallmainsegxendssubr1procnear……retsegysegment……farptrsubt……subr1endpcallcodeendssegyends例：十六进制到十进制的转换（通过寄存器传送参数）hexidecsegmentassumecs:procpushsubpush;1610hexidecmainstart:fardsax,axaxrepeat:callcallcallcalljmpretendphexibincrlfbinideccrlfrepeat;162;210main………………hexidecendsendstartbinidecprocnearhexibinprocnearmovcx,10000dcalldec_divmovcx,1000dcalldec_divmovcx,100dcalldec_divmovcx,10dcalldec_divmovcx,1dcalldec_divretmovbx,0newchar:movah,1int21hsubal,30hjlexitcmpal,10jladd_tosubal,27hcmpal,0ahjlexitcmpal,10hjgeexitadd_to:binidecendpmovcl,4shlbx,clmovah,0addbx,axjmpnewchardec_divprocnearmovax,bxmovdx,0divcxmovbx,dxmovdl,aladddl,30hmovah,2int21hretexit:rethexibinendp1ab531616235dec_divendp例：累加数组中的元素（通过存储器传送参数）datasegmentarycountsumendssegmentprocassumemovmovdwdwdw1,2,3,4,5,6,7,8,9,1010?datacodemainproaddprocnearfarcs:code,ds:dataax,datads,axpushaxpushcxpushsileasi,arymovcx,countxorax,axcallproaddnext:addax,[si]addsi,2loopnextmovsum,axpopsipopcxpopaxretmovintendpax,4c00h21hmaincodeendsendmainproaddendp如果数据段定义如下：datasegmentarydwcountdwsumdw1,2,3,4,5,6,7,8,9,1010?ary1dwcount1dwsum1dw10,20,30,40,50,60,70,80,90,10010?dataends如果直接访问内存变量，那么累加数组ary和数组ary1中的元素不能用同一个子程序proadd。例：累加数组中的元素（通过地址表传送参数地址）datasegmentarycountsumtableendssegmentprocassumecs:code,ds:datapushsubpushmovmovmovtable,offsetarymovtable+2,offsetcountmovtable+4,offsetsummovbx,offsettablecallproaddretdwdwdwdw10,20,30,40,50,60,70,80,90,10010?3dup(?);地址表datacodemainfardsax,axaxax,datads,axmainendp例：累加数组中的元素（通过堆栈传送参数地址）datasegmentarycountsumendsdw10,20,30,40,50,60,70,80,90,100dw10dw?datastacksegmentdwtos100labeldup(?)wordstackendscode1segmentmainprocfarassumecs:code1,ds:data,ss:stackstart:movax,stackmovss,axmovsp,offsettosmovax,datamovds,axmovbx,offsetarypushbxmovbx,offsetcountpushbxmovbx,offsetsumpushbxcallfarptrproaddmovax,4c00hint21hmainendpcode1endscode2segmentassumecs:code2proaddprocfarxorax,axpushbpmovbp,spnext:addax,[si]addsi,2loopnextmov[di],ax(sp)(di)(si)(cx)(ax)pushaxpushcxpushsipushdi(bp)(bp)

(ip)popdipopsipopcxpopaxmovsi,[bp+0ah]movdi,[bp+8]movcx,[di]movdi,[bp+6](cs)sumcountarray(bp)+6(bp)+8popbp(bp)+0ahret6toscode2endsproaddendpendstartreversprocnear例：将字符串反序输出pushaxpushbxpushdxpushbpmovbp,spmovbx,[bp+10]moval,[bx]cmpal,'$'jnere_calljmpreturnincbxpushbxcallreverspopbxmovdl,[bx]movah,2int21hpopdxpopbxpopaxret主程序：strdb‘happy!