【正文】 .code main PROC mov eax,10000h 。 display registers exit main ENDP END main directive marks ment ment copy definitions from code segment. 3 segments: code, data, stack beginning of a procedure source destination mark the last line and startup procedure defined in to end a program Example output Program output, showing registers and flags: EAX=00030000 EBX=7FFDF000 ECX=00000101 EDX=FFFFFFFF ESI=00000000 EDI=00000000 EBP=0012FFF0 ESP=0012FFC4 EIP=00401024 EFL=00000206 CF=0 SF=0 ZF=0 OF=0 Suggested coding standards (1 of 2) ? Some approaches to capitalization – capitalize nothing – capitalize everything – capitalize all reserved words, including instruction mnemonics and register names – capitalize only directives and operators (used by the book) ? Other suggestions – descriptive identifier names – spaces surrounding arithmetic operators – blank lines between procedures Suggested coding standards (2 of 2) ? Indentation and spacing – code and data labels – no indentation – executable instructions – indent 45 spaces – ments: begin at column 4045, aligned vertically – 13 spaces between instruction and its operands ? ex: mov ax,bx – 12 blank lines between procedures Alternative version of AddSub TITLE Add and Subtract () 。 EAX = 30000h call DumpRegs INVOKE ExitProcess,0 main ENDP END main Program template TITLE Program Template () 。 Revisions: 。 (insert additional procedures here) END main Assemblelink execute cycle ? The following diagram describes the steps from creating a source program through executing the piled program. ? If the source code is modified, Steps 2 through 4 must be repeated. S ou r c eF i l eO bj ec tF i l eLi s ti ngF i l eLi nkLi brar yE x ec uta bl eF i l eMapF i l eO utp utS t e p 1 : t e x t e d it o rS t e p 2 :a s s e mblerS t e p 3 :li n k e rS t e p 4 :OS loa d e r ? Called a batch file ? Run it to assemble and link programs ? Contains a mand that executes (the Microsoft Assembler) ? Contains a mand that executes (the 32bit Microsoft Linker) ? CommandLine syntax: make32 progName (progName includes the .asm extension) (use to assemble and link Realmode programs) Listing file ? Use it to see how your program is piled ? Contains – source code – addresses – object code (machine language) – segment names – symbols (variables, procedures, and constants) ? Example: Defining data ? Intrinsic data types ? Data Definition Statement ? Defining BYTE and SBYTE Data ? Defining WORD and SWORD Data ? Defining DWORD and SDWORD Data ? Defining QWORD Data ? Defining TBYTE Data ? Defining Real Number Data ? Little Endian Order ? Adding Variables to the AddSub Program ? Decl