學 Win32 匯編[22] - 邏輯運算指令: AND、OR、XOR、NOT、TEST
阿新 • • 發佈：2017-07-22
xor 原來 .lib 標誌位 cal loop win text model
AND: 邏輯與
;該指令會置 CF=OF=0; 其結果影響 SF、ZF、PF ;指令格式: AND r/m, r/m/i
; Test22_1.asm - 使用 AND 運算將一個數的第二、四位清零 .386 .model flat, stdcall include windows.inc include kernel32.inc include masm32.inc include debug.inc includelib kernel32.lib includelib masm32.lib includelib debug.lib .code main procmov al, 00001111b and al, 11110101b PrintHex al ;05 - 00000101b ret main endp end main
; Test22_2.asm - 使用 AND 運算將字母轉大寫 .386 .model flat, stdcall include windows.inc include kernel32.inc include masm32.inc include debug.inc includelib kernel32.lib includelib masm32.lib includelibdebug.lib .data szText db ‘Delphi‘, 0 .code main proc lea esi, szText mov ecx, lengthof szText - 1 @@: and byte ptr [esi], 11011111b ;大寫字母和小寫字母只有第五位不同 inc esi loop @B PrintString szText ;DELPHI ret main endp end main
OR: 邏輯或
;該指令會置 CF=OF=0; 其結果影響 SF、ZF、PF ;指令格式: OR r/m, r/m/i
; Test22_3.asm - 使用 OR 運算確保一個數的第二、四位是 1 .386 .model flat, stdcall include windows.inc include kernel32.inc include masm32.inc include debug.inc includelib kernel32.lib includelib masm32.lib includelib debug.lib .code main proc mov al, 11110001b or al, 00001010b PrintHex al ;FB - 11111011b ret main endp end main
; Test22_4.asm - 使用 OR 運算將字母轉小寫 .386 .model flat, stdcall include windows.inc include kernel32.inc include masm32.inc include debug.inc includelib kernel32.lib includelib masm32.lib includelib debug.lib .data szText db ‘Delphi‘, 0 .code main proc lea esi, szText mov ecx, lengthof szText - 1 @@: or byte ptr [esi], 00100000b ;大寫字母和小寫字母只有第五位不同 inc esi loop @B PrintString szText ;delphi ret main endp end main
XOR: 邏輯異或
;該指令會置 CF=OF=0; 其結果影響 SF、ZF、PF ;指令格式: XOR r/m, r/m/i
; Test22_5.asm - 兩次和一個相同的數 XOR 恢復到原來的數 .386 .model flat, stdcall include windows.inc include kernel32.inc include masm32.inc include debug.inc includelib kernel32.lib includelib masm32.lib includelib debug.lib .code main proc mov eax, 12345 xor eax, 88888888 PrintDec eax ;88892929 xor eax, 88888888 PrintDec eax ;12345 ret main endp end main
; Test22_6.asm - 使用 XOR 加密與解密字符串 .386 .model flat, stdcall include windows.inc include kernel32.inc include masm32.inc include debug.inc includelib kernel32.lib includelib masm32.lib includelib debug.lib .data szText db ‘Hello World!‘, 0 .code main proc ;加密 lea esi, szText mov ecx, lengthof szText - 1 @@: xor byte ptr [esi], 123 ;使用 123 做密碼 inc esi loop @B PrintString szText ;顯示亂碼 ;解密 lea esi, szText mov ecx, lengthof szText - 1 @@: xor byte ptr [esi], 123 inc esi loop @B PrintString szText ;Hello World! ret main endp end main
NOT: 邏輯取反
;該指令不影響 EFlags ;指令格式: NOT r/m
; Test22_7.asm - 使用 NOT 加密與解密字符串 .386 .model flat, stdcall include windows.inc include kernel32.inc include masm32.inc include debug.inc includelib kernel32.lib includelib masm32.lib includelib debug.lib .data szText db ‘Hello World!‘, 0 .code main proc ;加密 lea esi, szText mov ecx, lengthof szText - 1 @@: not byte ptr [esi] inc esi loop @B PrintString szText ;顯示亂碼 ;解密 lea esi, szText mov ecx, lengthof szText - 1 @@: not byte ptr [esi] inc esi loop @B PrintString szText ;Hello World! ret main endp end main
TEST: 測試邏輯與
;該指令會置 CF=OF=0; 其結果影響 SF、ZF、PF ;指令格式: TEST r/m, r/m/i ;TEST 同 AND, 但它不修改運算數, 只改變標誌寄存器; 也就是嘗試 AND 的結果 ;常用到它對 ZF 的影響(結果為0時ZF=1) ;TEST 之後常常跟著條件跳轉指令 JZ、JNZ
; Test22_8.asm - 觀察 TEST 之後的零標誌位(ZF) .386 .model flat, stdcall include windows.inc include kernel32.inc include masm32.inc include debug.inc includelib kernel32.lib includelib masm32.lib includelib debug.lib .code main proc ;判斷字母 A 二進制(01000001)的其最後一位是否是 0, 如果是 0 那麽 ZF=1 mov al, ‘A‘ test al, 00000001b lahf PrintHex ah ;02 - 00000010b (ZF=0) ;判斷字母 B 二進制(01000010)的其最後一位是否是 0, 如果是 0 那麽 ZF=1 mov al, ‘B‘ test al, 00000001b lahf PrintHex ah ;46 - 01000110b (ZF=1) ;判斷 ecx 是否為空 mov ecx, 1 test ecx, ecx lahf PrintHex ah ;06 - 00000010b (ZF=0, 不為空) xor ecx, ecx test ecx, ecx lahf PrintHex ah ;06 - 01000110b (ZF=1, 為空) ret main endp end main
; Test22_9.asm - 判斷字符串中每個字符的二進制位的最後一位是 1 還是 0 .386 .model flat, stdcall include windows.inc include kernel32.inc include masm32.inc include debug.inc includelib kernel32.lib includelib masm32.lib includelib debug.lib .data szText db ‘Delphi‘, 0 .code main proc ;清空兩個寄存器用於計數 xor eax, eax xor edx, edx lea esi, szText ;字符串地址 mov ecx, lengthof szText - 1 ;字符串長度 L1: test byte ptr [esi], 00000001b ;循環測試每個字符的最後一位是 1 還是 0 jz L2 ;如果是 0 則跳到 L2 給 edx+1 inc eax ;反之給 eax+1 jmp L3 L2: inc edx L3: inc esi loop L1 PrintDec eax ;2 - 這是最後一位是 1 的字符的個數: e、i PrintDec edx ;4 - 這是最後一位是 0 的字符的個數: D、l、p、h ret main endp end main
學 Win32 匯編[22] - 邏輯運算指令: AND、OR、XOR、NOT、TEST