学 Win32 汇编[21] - 传送指令: MOV、LEA、XCHG、XLATB、XLAT、MOVZX、MOVSX

汇编指令的一般性要求: 1、两个操作数的尺寸必须一致; 2、操作数不能同为内存.

MOV(Move): 最常用的数据传送指令

;该指令不影响 EFlags;指令格式: (其中的 r、m、i 分别表示: 寄存器、内存、立即数)MOV r/m, r/m/i; Test21_1.asm.386.model flat, stdcallinclude    windows.incinclude    kernel32.incinclude    masm32.incinclude    debug.incincludelib kernel32.libincludelib masm32.libincludelib debug.lib.data??   val dd ?.codemain proc?   mov val, 123?   mov edx, val?   mov eax, edx?   PrintDec eax ;123?   retmain endpend main

LEA(Load Effective Address): 有效地址传送指令

;该指令不影响 EFlags;指令格式:LEA r, m; Test21_2.asm.386.model flat, stdcallinclude    windows.incinclude    kernel32.incinclude    masm32.incinclude    debug.incincludelib kernel32.libincludelib masm32.libincludelib debug.lib.data?   szText db 'ABCDEFG', 0.codemain proc?   lea eax, offset szText?   lea ebx, szText?   PrintHex eax ;00403000?   PrintHex ebx ;00403000?   retmain endpend main

XCHG(Exchange): 交换指令

;该指令不影响 EFlags;指令格式:XCHG r/m, r/m; Test21_3.asm.386.model flat, stdcallinclude    windows.incinclude    kernel32.incinclude    masm32.incinclude    debug.incincludelib kernel32.libincludelib masm32.libincludelib debug.lib.data?   val1 dd 111?   val2 dd 222.codemain proc?   mov eax, val1?   xchg eax, val2?   mov val1, eax?   PrintDec val1 ;222?   PrintDec val2 ;111?   retmain endpend main

XLATB(Translate Byte)、XLAT(Translate): 换码指令

;XLATB 可简化为 XLAT;该指令不影响 EFlags;XLAT 无参数, 操作和 EBX、AL 相关;执行 XLAT 前, 先把源地址放入 EBX, 把字节序号放入 AL;执行后, 指定字节被读入 AL; Test21_4.asm.386.model flat, stdcallinclude    windows.incinclude    kernel32.incinclude    masm32.incinclude    debug.incincludelib kernel32.libincludelib masm32.libincludelib debug.lib.data?   szText db 'ABCDEFG', 0.codemain proc?   lea ebx, szText?   mov al, 1?   xlat?   PrintHex al ;42 - 这是 'B' 的 ASSII 编码?   ?   mov al, 2?   xlatb?   PrintHex al ;43 - 这是 'C' 的 ASSII 编码?   retmain endpend main

MOVZX(Move With Zero-Extend): 零扩展传送

;该指令不影响 EFlags;指令格式:MOVZX r32, r16/m16MOVZX r16, r8/m8;示例同 MOVSX

MOVSX(Move With Sign-Extend): 符号扩展传送

;该指令不影响 EFlags;指令格式:MOVZX r32, r16/m16MOVZX r16, r8/m8;MOVZX 和 MOVSX 的区别是:;1、MOVZX 会将目标寄存器中高出的位补 0;2、如果源操作数的最高位是 1, MOVSX 会将目标寄存器中高出的位补 1; 反之补 0; Test21_5.asm.386.model flat, stdcallinclude    windows.incinclude    kernel32.incinclude    masm32.incinclude    debug.incincludelib kernel32.libincludelib masm32.libincludelib debug.lib.data?   bVal   db 90h?   dwVal1 dw 7FFFh?   dwVal2 dw 8000h.codemain proc?   movzx eax, dwVal1?   movsx edx, dwVal1?   PrintHex eax ;00007FFF?   PrintHex edx ;00007FFF?   ?   movzx eax, dwVal2?   movsx edx, dwVal2?   PrintHex eax ;00008000?   PrintHex edx ;FFFF8000?   ?   mov cl, bVal?   movzx ax, cl?   movsx dx, cl?   PrintHex ax  ;0090?   PrintHex dx  ;FF90?   retmain endpend main