與-101x86第一個(gè)匯編程序及其它

$gcc- Thiswillproduceafile n:theoptimization$gcc–S-

main; .rdata,

o

$0, $0, .def_exit;.scl3;.type32;.def_printf;.scl3;.type32;

_main;%esp,$8,$-16,$0,$15,$15,$4,$4,%eax,--4(%ebp),

gccgcc- alloca main

$LC0, main;

.rdata, o

_main;%esp,$8,$-16,$0,$15,$15,$4,$4,%eax,--4(%ebp),

gccgcc- alloca main

$0,

$LC0,

.def_exit;.scl3;.type32;.def_printf;.scl3;.type32; main;

.rdata, oworld\12\0”.globl

_main;

$16,

%esp,$8, gcc- oworld.c- $-16, alloca 版本３.４.４(32位) main $LC0, $0, "o

_main;

$16,%esp,$8,$-16,$LC0,$0,匯編代碼中以“.”開頭的行都是匯編代碼中以“.”開頭的行都是匯編指示（Directives），如“.file”def”text main; #.defdirectivesdefinesadebugging#.scl2meansstorageclass(externalstorageclass)#.type32saysthissymbolisafunction.

地址的符號(hào)（Symbol）示例示例指示匯編器符號(hào)“_main”是全局的，這樣同一程序的其它模塊可它則則不是全局可見.p2align#指定下一行代碼的對(duì)齊方式：第1參數(shù)表示按2的多少次冪第216.section.rdata,.ascii o.globl.align1請(qǐng)嘗試解釋一下intc1局變

oworld.c main; .ascii o.p2align.globl

#1615字節(jié)，則不對(duì)齊 _main; $16,%esp,$8,$-16,$LC0,$0,_puts; _exit; oworld.c "o.p2align.globl

#1615字節(jié)，則不對(duì)齊

%esp,$4,

關(guān)#分配4字節(jié)堆棧關(guān)

gcc-O2-mpreferred- main

oworld.c-

$LC0,$0,

oworld.c main;

.ascii o

#1615關(guān)oworld.c關(guān)oworld.c-gcc-O2-mpreferred-stack-boundary=2-fomit-$4,$LC0,$0,charbig_array[1<<24];/*16MBcharhuge_array[1<<28];/*256MB char*p1,*p2,*p3,intuseless(){return0;int{p1=malloc(1<<28);p2=malloc(1<<8);p3=malloc(1<<28);p4=malloc(1<<8);

/*256MB/*256B/*256MB/*256B/*Someprintstatements...}finalmalloc()

&p2finalmalloc()

addressrange &p2 as-omy-object- //ld–omy-exe-filemy-object-64位環(huán)境下添加命令行參數(shù)：-moworld

len

o $len,

$msg,$1,$4,$0,$1,

#系統(tǒng)輸出（writeint80寄存器eax中存放的是系統(tǒng)調(diào)用的功能號(hào)，而傳給系統(tǒng)調(diào)用的數(shù)則必須按順序放到寄存器ebx，ecx，edx，esi，edi中當(dāng)系統(tǒng)調(diào)用完成之后，返回值可以在寄存器eax中獲需將系統(tǒng)調(diào)用功能號(hào)保存在寄存器eax中，全部參數(shù)依次放在一ebx中保存指向該內(nèi)存區(qū)域系統(tǒng)調(diào)用完成之后，返回值仍將保存在寄存器eax中1(Thiscalldoesnotfork-createchild20intheprocessidofcloneororENOMEMinread-readfromfileor3fileaddressofthebuffertoumnumberofbytesnumberofbytesactually|EAGAIN|EBADF|EFAULTEINTR|EINVAL|EIO|close-closeafileor6filezeroforsuccess|waitpid-waitforaprocessesto7processidoftheprocessto0,oraddressofbuffertoexitoptionflags|0|WNOHANGpidoffinishedprocess||EINVAL|exitstateoffinishedprocess,non-zerovaluewasinputincreate-createa8addressofzero-filepermissionfiledescriptorofopenedfileEACCESS|EEXIST|EFAULTEISDIR|ELOOP|EMFILE,LONG|ENFILEENOENT|ENODEV|ENODIRENOMEM|ENOSPC|ENXIOEROFS|unlink-deleteanameandremovefilewhennotaddressofzero-terminatedpathnameexistingfile0|EACCES|EFAULT|EIO|EISDIR|ELOOP LONG|ENOENT|ENOMEMENOTDIR|EPERM|execve-executeaaddressofzero-terminatedpathnameaddressofzero-terminatedlistofofzero-terminatedargumentaddressofzero-terminatedlistofofzero-terminatedenvironmentIfsuccess,noreturnbecausethenewprograminheritsresourcesandoverwritescaller;otherwise:E2BIG|EACCES|EINVAL|EIO|EISDIR|ELIBBAD|ELOOP|ENFILE|ENOEXEC|ENOENT|ENOMEM|ENOTDIR|EFAULT|ENA LONG|EPERM|chdir-changeworkingaddressofzero-terminatedpathnameexisting0|EACCES|EBADF|EFAULT|EIO|ELOOPLONG|ENOENT|ENOMEM .globl

#

%ecx,%ecx%ecx,%edx,(%ebx),%al,%al$10,-$4,$1,%ebx,

#時(shí)，其所需的參數(shù)(argcargv)將sys_write)#文件描述符(stdout)指指 入。EAX寄存器用于決定CPUID指令EAX存器的值，CPUID指令在EBX，ECX和EDX寄存（0）值被EAX寄存器并且執(zhí)行CPUID令時(shí)，處理器把廠商ID字符串返回到EBX，EDXECXEBX最低個(gè)字EDX中間個(gè)字ECX最高個(gè)字 "Theprocessvendoridis.sectionm.section

$0,$buffer, %ebx, %edx, %ecx,$as-ocpuid.o

$ld-lc-dynamic-linker/lib/ld-linux.so.2-ocpuid 匯編器使用_start符號(hào)表示默認(rèn)的起始點(diǎn),此外如果想要匯編 ,需要賦予.globl屬性,如:.globl只讀數(shù)據(jù)段一個(gè)數(shù)據(jù)元素時(shí),需要使用Symbol示例如下.ascii o .float 可以在一行中定義多個(gè)值如.int20,10,30,

.32.long32位整數(shù)和int.octa16.quad8.short16.single單精度浮點(diǎn)數(shù)(和float相同和data段不同,無需 特定的數(shù)據(jù)類型,只需 示例如下.sectionmbuffer,#該語句把1000字節(jié)的內(nèi)存地址賦予buffer外部模塊不能相相比較.data段，.bss 的優(yōu)點(diǎn)是.section.data.long.section.globlmovl$0,movldata_items(,%edi,4),%eaxmovl%eax,%ebxcmpl$0,%eaxjeloop_exitincl%edimovldata_items(,%edi,4),%eaxcmpl%ebx,%eaxjlemovl%eax,%ebxjmpstart_loopmovl$1,int

#1istheexit().section #Thesearethedata.long.section.globlmovl$0,%edi #move0intotheindexregistermovldata_items(,%edi,4),%eax#loadthefirstdatamovl%eax, #sincethisisthefirstitem,%eax#thecmpl$0,%eaxjeloop_exit

#start#checktoseeifwe'vehittheincl%edi #loadnextvaluemovldata_items(,%edi,4),%eaxcmpl%ebx,jlemovl%eax,%ebxjmpstart_loop

#compare#jumptoloopbeginningifthe#oneisn't#movethevalueasthelargest#jumptoloopbeginningmovlmovl$1,#1istheexit()int#%ebxisthestatuscodefortheexitsystem #anditalreadyhasthe um 補(bǔ)充：算術(shù)操作指指效描imullR[%edx]:R[%eax]=S*無符號(hào)64位mullR[%edx]:R[%eax]=S*有符號(hào)64位 R[%edx]:R[%eax]=符號(hào)位擴(kuò)展轉(zhuǎn)換為4字idivlR[%edx]=R[%edx]:R[%eax]%R[%eax]=R[%edx]:R[%eax]/divlR[%edx]=R[%edx]:R[%eax]%R[%eax]=R[%edx]:R[%eax]/64位數(shù)通 .section.globlpushlsecondpushlfirstcalltheaddl$8,thestackpointerpushlthefirstpushl$2pushl$5callpoweraddl$8,%esp

#pushsecondargument#pushfirstargument#callthefunction#movethestackpointersecondanswerisin%eax.We%eax,thefirstoutinto%ebxthemtogether;theresultisin%ebxmovl$1,%eax #exit(%ebxisreturned)int$0x80.typepower,@functionpushl%ebpmovl%esp,%ebpsubl$4,%espmovl8(%ebp),%ebxmovl12(%ebp),%ecxmovl%ebx,-

為何還要保存%ebp等操#saveoldbase#makestackpointerthebase#getroomforourlocalstorage#putfirstargumentin%eax#putsecondargumentin%ecx#storecurrentresultcmpl$1,%ecxjeend_power

#ifthepoweris1,wearemovl-4(%ebp),%eax#movethecurrentresultintoimull%ebx, #multiplythecurrentresultbythebasemovl%eax,-4(%ebp)#storethecurrentdecl #decreasethejmppower_loop_start#runforthenextmovl-4(%ebp),%eax#returnvaluegoesinmovl%ebp,popl

#restorethestack#restorethebase.type.typepower, lsthelinkerthatthesymbolpowershouldbetreatedasa階乘.section.globl #thisisunneededunlesswewanttoshare.globlpushlcall

#Thefactorialtakesoneargument–#thenumberwewantafactorialof.#runthefactorialfunction$4,#restorethe%eax,#factorialreturnstheanswerin%eax,but$1,#wantitin%ebxtosenditasourexit#callthekernel’sexitint#Thisistheactualfunction factorial,pushl

%esp,8(%ebp), #Thismovesthefirstargumenttocmpl$1, #Ifthenumberis1,thatisourbasecase,#wesimplyreturn(1isalreadyin%eaxas#returnjedecl #otherwise,decreasethepushl #pushitforourcalltocall #callmovl8(%ebp), #%eaxhasthereturnvalue,sowereload#parameterintoimull%ebx, #multiplythatbytheresultofthelastcall#factorial(in%eax);theanswerisstoredmovl%ebp,%esppopl%ebpStep1:Step2:Step3:如果輸入文件 位置已到文件尾，則轉(zhuǎn)Step7；Step4: Step5:遍歷該內(nèi)容，將其中的小寫字母轉(zhuǎn)換成大寫；Step6:將轉(zhuǎn)換后的該內(nèi)容寫入輸出文件，轉(zhuǎn)Step3；Step7:程序結(jié)束。.equ用于把常量值設(shè)置為可以在程序中使用的.equfactor,.equLINUX_SYS_CALL,經(jīng)過設(shè)置之后，數(shù)據(jù)符號(hào)值是不能在程序中改動(dòng)的#######toupper.s#systemcall.equSYS_OPEN,.equSYS_WRITE,.equSYS_READ,.equSYS_CLOSE,.equSYS_EXIT,#optionsforO_RDONLY,O_PERMISSION,#standardfile.equSTDIN,.equSTDOUT,.equSTDERR,#systemcall.equLINUX_SYSCALL,.equEND_OF_FILE,0#Thisisthereturnvalueofreadwhichmeans#hittheendofthe.section.section#Buffer-thisiswherethedataisloadedintofromthe#fileandwrittenfromintotheoutput.equBUFFER_SIZE,mBUFFER_DATA,.section#STACKST_FD_IN,-ST_FD_OUT,-8ST_ARGC,#NumberofST_ARGV_0,#NameofST_ARGV_1,ST_ARGV_2,#Inputfile#Outputfile.globl###INITIALIZEmovl%esp,subl$ST_SIZE_RESERVE,%esp#Allocatespaceforour$SYS_OPEN,#openST_ARGV_1(%ebp),#inputfilenameinto$O_RDONLY,$O_PERMISSION,intmovl%eax, #savethegivenfilemovl$SYS_OPEN,movlST_ARGV_2(%ebp),

#openthemovl$O_CREAT_WRONLY_TRUNC, #flagsforwritingtothe#modefornewmovl$O_PERMISSION,%edxint$LINUX_SYSCALL#storethefiledescriptorheremovl%eax,ST_FD_OUT(%ebp)###BEGINMAINmovl$SYS_READ,movlST_FD_IN(%ebp),%ebx #gettheinputfiledescriptormovl$BUFFER_DATA,%ecx #thelocationtoreadintomovl$BUFFER_SIZE,%edx #thesizeofthebufferint #Sizeofbufferreadisreturned###EXITIFWE’VEREACHEDTHEcmpl$END_OF_FILE,%eaxjleend_loop

#checkforendoffile#iffoundoronerror,gotothe###CONVERTTHEBLOCKTOUPPERpushlpushlcallpopl%eaxaddl$4,%esp

#locationof#sizeofthe#getthesizeback#restore%esp###WRITETHEBLOCKOUTTOTHEOUTPUTmovl%eax,movl$SYS_WRITE,movlST_FD_OUT(%ebp),%ebxmovl$BUFFER_DATA,%ecxint$LINUX_SYSCALL###CONTINUETHEjmp

#sizeofthe#theoutputfile#locationofthe###CLOSETHEmovl$SYS_CLOSE,movlST_FD_OUT(%ebp),intmovl$SYS_CLOSE,%eaxmovlST_FD_IN(%ebp),%ebxint$LINUX_SYSCALLmovl$SYS_EXIT,movl$0,int#convert_to_upper#INPUT:Thefirstparameteristhelocationoftheblockofmemory#Thesecondparameteristhelengthofthat#OUTPUT:Thisfunctionoverwritesthecurrentbufferwiththe.equLOWERCASE_A,.equLOWERCASE_Z,

#Thelowerboundaryofoursearch#Theupperboundaryofour.equUPPER_CONVERSION,’A’-###STACK.equST_BUFFER_LEN,.equST_BUFFER,

#Lengthof#actualpushl%ebpmovl%esp,%ebp#ifabufferwithzerolengthwasgiventous,justcmpl$0,jemovb(%eax,%edi,1),cmpb$LOWERCASE_A,jlcmpb$LOWERCASE_Z,jg

#getthecurrent#gotothenextbyteunlessit###SET###SETUPmovlST_BUFFER(%ebp),movlST_BUFFER_LEN(%ebp),movl$0,#loop#otherwiseconvertthebytetouppercase,andstoreitaddb$UPPER_CONVERSION,movb%cl,inclcmpl%edi,%ebxjneconvert_loopmovl%ebp,%esppopl%ebp

#next#continueunlesswe’vereachedthe#Common#CommonLinux#SystemCall.equSYS_EXIT,.equSYS_READ,.equSYS_WRITE,.equSYS_OPEN,.equSYS_CLOSE,.equSYS_BRK,#SystemCallInterrupt.equLINUX_SYSCALL,#StandardFile.equSTDIN,.equSTDOUT,.equSTDERR,#CommonStatus.equEND_OF_FILE,.equRECORD_FIRSTNAME,.equRECORD_LASTNAME,.equRECORD_ADDRESS,.equRECORD_AGE,.equRECORD_SIZE,使用時(shí).include.include"record-#read-.include"record-.include#INPUT:Thefiledescriptoranda#OUTPUT:Thisfunctionwritesthedatatothebufferandreturns#STACKLOCAL.equST_READ_BUFFER,.equST_FILEDES,

.section.globl.typeread_record,pushlmovl%esp,pushlmovlST_FILEDES(%ebp),%ebxmovlST_READ_BUFFER(%ebp),%ecxmovl$RECORD_SIZE,%edxmovl$SYS_READ,int

#NOTE-%eaxhasthereturnvaluepopl%ebxmovl%ebp,popl#write-.include.include"record-#INPUT:Thefiledescriptoranda#OUTPUT:Thisfunctionproducesastatus#STACKLOCAL.equST_WRITE_BUFFER,.equST_FILEDES,.section.globl.typewrite_record,@functionpushl%ebpmovl%esp,%ebppushl%ebxmovl$SYS_WRITE,movlST_FILEDES(%ebp),%ebxmovlST_WRITE_BUFFER(%ebp),%ecxmovl$RECORD_SIZE,%edxint

#NOTE-%eaxhasthereturnpoplmovl%ebp,popl%ebp#write-.include.include"record-.section.data.ascii.rept31#Paddingto40.byte

OpentheWritethreeClosethe.ascii.rept31#Paddingto40.ascii.rept31#Paddingto40.byte

“.reptN”209#Paddingto2400填充其與“.endr”之間容，重復(fù)N…

#skiprecord2~#Thisisthenameof.ascii

filewewillwrite.equST_FILE_DESCRIPTOR,-.globlmovl%esp,subl$4,%esp #Allocatespacetoholdthefiledescriptormovl$SYSOPEN%eaxaswrite-records.s-owrite-record.oaswrite-record.s-owrite-ldwrite-record.owrite-records.o-owrite-movl%eax,ST_FILE_DESCRIPTOR(%ebp)#Storethefilepushlpushl$record1callwrite_recordaddl$8,%esp

#Writethefirst#Writetheremainingrecords;closethefileand…OpentheAttempttoreadaIfweareattheendofthefile,Otherwise,countthecharactersofthefirstWritethefirstnametoWriteanewlinetoGobacktoreadanother#count-#INPUT:Theaddressofthe#OUTPUT:Returnsthecountin.typecount_chars,.globl.equST_STRING_START_ADDRESS,pushl

%esp,$0, #CounterstartsatmovlST_STRING_START_ADDRESS(%ebp), #Startingaddressofmovb(%edx),%alcmpb$0,%aljecount_loop