3.2 integer addition and subtraction
TITLE the Add and Substract ; TITLE line comments ; author: Hk_Mayfly ; DATE: 2019/09/06 . Irvine32 the INCLUDE inc is ; calling function .code ; snippet main PROC ; start a process of identifying PROC (corresponding to a function defined flags start) MOV EAX, 10000H ; the Add EAX, 20000H Sub EAX, 10000H call DumpRegs ; call a display process CPU register values of main ENDP ; and 16-bit code ends Similarly, ENDP indicating the end of a process the eND main ; and the end start similar, showing assembler end, main reference numeral identifies the entry address process
TITLE the Add and Substract ; TITLE line comments ; author: Hk_Mayfly ; DATE: 2019/09/06 . Irvine32 the INCLUDE inc is ; the calling function . 386 ; procedure requires a minimum the CPU .model Flat, _stdcall ; .model generating code for the protected mode program .stack 4096 ; the ExitProcess PROTO, dwExitCode: DWORD DumpRegs PROTO ; PROTO prototype declaration process used by the program, corresponding to the function declaration .code ; snippet main PROC ; start a process of identifying PROC (corresponding to mark the start of a function definition ) MOV EAX, 10000H ; the Add EAX, 20000H Sub EAX, 10000H Call DumpRegs ; call a display process of the CPU registers the INVOKE the ExitProcess, 0 ; return 0, the function call corresponds to the main ENDP ; and 16-bit code ends Similarly, ENDP indicating the end of a process the END main ; and similar end start, represents the end of the assembler, main reference numeral identifies the entry address process
3.3 Assembler link execution cycle
3.4 Defining Data
Data definition syntax:
[name] directive initializer [,initializer]...
The following is an example of a data definition statement:
count DWORD 12345
| Types of | usage |
|---|---|
| BYTE | 8-bit unsigned integer, B for byte |
| SBYTE | 8-bit signed integer, S for signed |
| WORD | 16-bit unsigned integer |
| SWORD | 16-bit signed integer |
| DWORD | 32-bit unsigned integer, D for double (word) |
| SDWORD | 32-bit signed integer, represent SD signed bis (word) |
| FWORD | 48 integers (far pointer protected mode) |
| QWORD | 64-bit integer, Q represents tetrakis (word) |
| TBYTE | 80 (10-byte) integer, T 10 bytes representatives |
| REAL4 | 32-bit (4-byte) the IEEE Short real |
| REAL8 | 64-bit (8-byte) length of the IEEE Real |
| REAL10 | 80 (10 bytes) extended the IEEE real |
You can also use
| Directive | usage | Directive | usage |
|---|---|---|---|
| DB | 8-bit integer | DQ | 64-bit integer or a real number |
| DW | 16-bit integer | DT | Definition of 80 (10 byte) integer |
| DD | 32-bit integer or a real number |
3.4.10 add a variable to AddSub
TITLE Add and Substract ;author:Hk_Mayfly ;date:2019/09/06 INCLUDE Irvine32.inc .data Num1 DWORD 10000H Num2 DWORD 20000H Num3 DWORd 30000H Sum Dword 0 .code main PROC mov eax,Num1 add eax,Num2 add eax,Num3 mov Sum,eax call DumpRegs exit main ENDP END main
3.4.12 exercises in this section
1.Val SWORD ?
2.Val BYTE ?
3.Val SBYTE ?
4.Val QWORD ?
5.SDWORD
6.Val SDWORD 10000000000000000000000000000000
7.wArray WORD 1,2,3
8.Color BYTE "Blue"
9.dArray DWORD 50 dup(?)
10.Val BYTE 500 dup('TEST')
11.bArray BYTE 20 dup(0)
12.21h,43h,65h,87h
3.5 symbolic constants
3.5.5 This section exercises
1.VK_BS = 08h 2.SecondsInDay = 24*60*60 3.ArraySize = ($-myArray) 4.ArraySize = ($-myArray)/4 5.PROCEDURE TEXTQU <PROC> 6.sample TEXTQU <"Hello_World"> MyString BYTE sample 7.SetupESI TEXTQU <mov esi,OFFSET myArray>
3.8 Programming Exercises
1, three integer subtraction
AddSub program reference in Section 3.2, prepare three 16-bit integer subtraction procedures, only need to use the program to register, the insertion function call DumpRegs statement to display the value of the register.
TITLE Add and Substract ;author:Hk_Mayfly ;date:2019/09/06 INCLUDE Irvine32.inc .data Num1 WORD 1000H Num2 WORD 2000H Num3 WORD 4000H .code main PROC mov eax,0 mov ax,Num3 sub ax,Num2 sub ax,Num1 call DumpRegs exit main ENDP END main
2, data defining
write a program, requires that all data types listed in the definition contained in section 3.4, with the appropriate initialization value of each variable
TITLE Add and Substract ;author:Hk_Mayfly ;date:2019/09/06 INCLUDE Irvine32.inc .data Num1 BYTE 'abc' Num2 SBYTE -10H Num3 WORD 1000H Num4 SWORD -1000H Num5 DWORD 10000H Num6 SDWORD -10000H Num7 FWORD 100000H Num8 QWORD 123456789ABCDEF0H Num9 TBYTE 123456789123456789H Num10 REAL4 2.56 Num11 REAL8 2.12345 Num12 REAL10 2.12345678 .code main PROC mov eax,0 mov al,[Num1+1] mov al,Num2 mov eax,0 mov ax,Num3 mov ax,Num4 mov eax,0 mov eax,Num5 mov eax,Num6 call DumpRegs exit main ENDP END main
3, signed integer constants
to write a program, the definition of symbols corresponding to one week of daily constants, variables and create an array using these symbols as the initial value
TITLE Add and Substract ;author:Hk_Mayfly ;date:2019/09/06 INCLUDE Irvine32.inc .data WEEK BYTE 'Mon' BYTE 'Tue' BYTE 'Wed' BYTE 'Thu' BYTE 'Fri' BYTE 'Sat' BYTE 'Sun' ;STR_LEN = ($-WEEK) .code main PROC mov eax,0 shr eax,16 mov al,[WEEK];'W' shl eax,16 mov ah,[WEEK+1];'e' mov al,[WEEK+2];'d' call DumpRegs exit main ENDP END main
4, the constant text symbol
to write a program to define several strings symbol names (characters enclosed in quotation marks). Each symbol used in the definitions of the variables are
TITLE Add and Substract ;author:Hk_Mayfly ;date:2019/09/06 INCLUDE Irvine32.inc .data Str1 TEXTEQU <"Hello_World!"> Str2 TEXTEQU <"I_Love_CTF!"> Str3 TEXTEQU <"REVE"> Str4 TEXTEQU <'Q'> .code main PROC mov eax,0 mov al,[Str4] mov eax,[Str3] call DumpRegs exit main ENDP END main
