汇编语言-008（条件跳转应用、loopnz 条件循环指令使用、loopz 条件循环指令使用、 if语句编写汇编时、while语句编写汇编时、循环内的if语句嵌套）

1：条件跳转应用，三个数中最小数

.386
.model flat,stdcall.stack 4096
ExitProcess PROTO,dwExitCode:DWORD.data
V1 WORD 1
V2 WORD 2
V3 WORD 3.code
main PROCmov ax,V1  ;假设V1是最小值cmp ax,V2  ;如果AX小于等于V2jbe L1mov ax,v2 
L1:cmp ax,V3jbe L2mov ax,V3
L2:INVOKE ExitProcess,0
main ENDP
END main

2：条件跳转应用，循环直到按下按键

.386
.model flat,stdcallinclude Irvine32.inc.stack 4096
ExitProcess PROTO,dwExitCode:DWORD.data
char BYTE ?.code
main PROCL1:mov eax,10call Delay  ;10毫秒的延迟call ReadKey ;检查按键jz L1        ;如果没有按键就循环mov char,AL  ;保存字符INVOKE ExitProcess,0
main ENDP
END main

3：条件跳转应用，顺序搜索数组

.386
.model flat,stdcallinclude Irvine32.inc.stack 4096
ExitProcess PROTO,dwExitCode:DWORD.data
intArray SWORD 0,0,0,0,1,20,35,-12,66,4,0
noneMsg BYTE "A non-zero value was not found",0.code
main PROCmov ebx,OFFSET intArraymov ecx,LENGTHOF intArray
L1:cmp WORD PTR[ebx],0jnz foundadd ebx,2loop L1jmp notFound
found:movsx eax,WORD PTR[ebx]call WriteIntjmp quit
notFound:mov edx,OFFSET noneMsgcall WriteString
quit:call CrlfINVOKE ExitProcess,0
main ENDP
END main

4：条件跳转应用，简单字符串加密

.386
.model flat,stdcall.stack 4096
ExitProcess PROTO,dwExitCode:DWORDinclude Irvine32.incKEY = 239
BUFMAX = 128.data
sPrompt BYTE "Enter the plain text:",0
sEncrypt BYTE "Cipher text: ",0
sDecrypt BYTE "Decrypted:  ",0
buffer BYTE BUFMAX+1 DUP(0)
bufSize DWORD ?.code
main PROCcall InputTheStringcall TranslateBuffermov edx,OFFSET sEncryptcall DisplayMessagecall TranslateBuffermov edx,OFFSET sDecryptcall DisplayMessageINVOKE ExitProcess,0
main ENDP;提示用户输入一个纯文本字符串
;保存字符串和它的长度
;接收：无
;返回：无
InputTheString PROCpushadmov edx,OFFSET sPromptcall WriteStringmov ecx,BUFMAXmov edx,OFFSET buffercall ReadStringmov bufSize,eaxcall Crlfpopadret
InputTheString ENDP;显示加密或解密消息
;接收：EDX指向消息
;返回：无
DisplayMessage PROCpushadcall WriteStringmov edx,OFFSET buffercall WriteStringcall Crlfcall Crlfpopadret
DisplayMessage ENDP;字符串的每个字符与密钥字节进行异或实现转换
;接收：无
;返回：无
TranslateBuffer PROCpushadmov ecx,bufSizemov esi,0
L1:xor buffer[esi],KEYinc esiloop L1popadret
TranslateBuffer ENDP
END main

5： loopnz 条件循环指令使用，查找数组第一个非负数

.386
.model flat,stdcall.stack 4096
ExitProcess PROTO,dwExitCode:DWORD.data
array SWORD -3,-6,-1,-10,10,30,40,4
sentinel SWORD 0.code
main PROCmov esi,OFFSET arraymov ecx,LENGTHOF array
L1:test WORD PTR[esi],8000h  ;测试符号位pushfd                    ;标志位入栈add esi,TYPE array        ;移动到下一个位置popfdloopnz L1                 ;当ZF=0时继续循环  jnz quit                  ;没有发现非负数sub esi,TYPE array        ;ESI指向数值
quit:INVOKE ExitProcess,0main ENDP
END main

6： loopz 条件循环指令使用，查找数组第一个负数

.386
.model flat,stdcall.stack 4096
ExitProcess PROTO,dwExitCode:DWORD.data
array SWORD 3,6,1,10,-10,-30,-40,-4
sentinel SWORD 0.code
main PROCmov esi,OFFSET arraymov ecx,LENGTHOF array
L1:test WORD PTR[esi],8000h  ;测试符号位pushfd                    ;标志位入栈add esi,TYPE array        ;移动到下一个位置popfdloopz L1                  ;当ZF=1时继续循环  jz quit                  ;没有发现非负数sub esi,TYPE array        ;ESI指向数值
quit:INVOKE ExitProcess,0main ENDP
END main

7： if语句编写汇编时的情况

.386
.model flat,stdcall.stack 4096
ExitProcess PROTO,dwExitCode:DWORD;if(al > bl) & (bl > cl)
;  X = 1.data
X DWORD ?.code
main PROCINVOKE ExitProcess,0
main ENDPproc_1 PROCcmp al,blja L1jmp nextL1:cmp bl,clja L2jmp nextL2:mov X,1next:
proc_1 ENDP;如果将ja 换成 jbe,代码减少2条
proc_2 PROCcmp al,bljbe nextcmp bl,cljbe nextmov X,1next:proc_2 ENDPEND main

8： if语句编写汇编时的情况

.386
.model flat,stdcall.stack 4096
ExitProcess PROTO,dwExitCode:DWORD.data
X DWORD ?;if(al > bl) || (bl > cl)
;X =1.code
main PROCcmp al,blja L1cmp bl,cljbe next
L1: mov X,1
next:INVOKE ExitProcess,0
main ENDP
END main

9： while语句编写汇编时的情况

.386
.model flat,stdcall.stack 4096
ExitProcess PROTO,dwExitCode:DWORD.data
val1 DWORD 10
val2 DWORD 20;while (val1 < val2)
;{
;   val1 ++;
;   val2 --;
;}.code
main PROCmov eax,val1
beginwhile:cmp eax,val2jnl endwhileinc eaxdec val2jmp beginwhile
endwhile:mov val1,eaxINVOKE ExitProcess,0
main ENDP
END main

10：循环内的if语句嵌套

.386
.model flat,stdcall.stack 4096
ExitProcess PROTO,dwExitCode:DWORD.data
sum DWORD 0
sample DWORD 50   ;计算数组所有大于sample的数之和
array DWORD 10,60,20,33,72,89,45,72,18
arraySize = ($ - array)/TYPE array.code
main PROCmov eax,0mov edx,samplemov esi,0mov ecx,arraySize
L1:cmp esi,ecxjl L2jmp L5
L2:cmp array[esi*4],edxjg L3jmp L4
L3:add eax,array[esi*4]
L4:inc esijmp L1
L5:mov sum,eaxINVOKE ExitProcess,0
main ENDP
END main