问题7.2

题目：用si和di将字符串'welcome to masm!' 复制到他后面的数据区中。

解答：第一种是没用si和di的，

源代码如下1：

assume cs:codesg,ds:datasgdatasg segment db 'welcome to masm!' db '................' datasg endscodesg segment start:mov ax,datasg mov ds,ax mov bx,0 mov cx,8h s:mov ax,[bx] mov [10h+bx],ax add bx,2 loop s mov ax,4c00h int 21h codesg endsend start

调试过程1:

-rAX=0000 BX=0000 CX=003A DX=0000 SP=0000 BP=0000 SI=0000 DI=0000 DS=143C ES=143C SS=144C CS=144E IP=0000 NV UP EI PL NZ NA PO NC 144E:0000 B84C14 MOVAX,144C -u144E:0000 B84C14 MOVAX,144C 144E:0003 8ED8 MOVDS,AX 144E:0005 BB0000 MOVBX,0000 144E:0008 B90800 MOVCX,0008 144E:000B 8B07 MOVAX,[BX] 144E:000D 894710 MOV[BX+10],AX 144E:0010 83C302 ADDBX,+02 144E:0013 E2F6 LOOP000B 144E:0015 B8004C MOVAX,4C00 144E:0018 CD21 INT21 144E:001A 52 PUSHDX 144E:001B 50 PUSHAX 144E:001C E89143 CALL43B0 144E:001F 83C404 ADDSP,+04 -d ss:0144C:0000 77 65 6C 63 6F 6D 65 20-74 6F 20 6D 61 73 6D 21 welcome to masm!144C:0010 2E 2E 2E 2E 2E 2E 2E 2E-2E 2E 2E 2E 2E 2E 2E 2E ................144C:0020 B8 4C 14 8E D8 BB 00 00-B9 08 00 8B 07 89 47 10 .L............G.-tAX=144C BX=0000 CX=003A DX=0000 SP=0000 BP=0000 SI=0000 DI=0000 DS=143C ES=143C SS=144C CS=144E IP=0003 NV UP EI PL NZ NA PO NC 144E:0003 8ED8 MOVDS,AX -tAX=144C BX=0000 CX=003A DX=0000 SP=0000 BP=0000 SI=0000 DI=0000 DS=144C ES=143C SS=144C CS=144E IP=0005 NV UP EI PL NZ NA PO NC 144E:0005 BB0000 MOVBX,0000 -tAX=144C BX=0000 CX=003A DX=0000 SP=0000 BP=0000 SI=0000 DI=0000 DS=144C ES=143C SS=144C CS=144E IP=0008 NV UP EI PL NZ NA PO NC 144E:0008 B90800 MOVCX,0008 -pAX=144C BX=0000 CX=0008 DX=0000 SP=0000 BP=0000 SI=0000 DI=0000 DS=144C ES=143C SS=144C CS=144E IP=000B NV UP EI PL NZ NA PO NC 144E:000B 8B07 MOVAX,[BX] DS:0000=6577-pAX=6577 BX=0000 CX=0008 DX=0000 SP=0000 BP=0000 SI=0000 DI=0000 DS=144C ES=143C SS=144C CS=144E IP=000D NV UP EI PL NZ NA PO NC 144E:000D 894710 MOV[BX+10],AX DS:0010=2E2E-pAX=6577 BX=0000 CX=0008 DX=0000 SP=0000 BP=0000 SI=0000 DI=0000 DS=144C ES=143C SS=144C CS=144E IP=0010 NV UP EI PL NZ NA PO NC 144E:0010 83C302 ADDBX,+02 -pAX=6577 BX=0002 CX=0008 DX=0000 SP=0000 BP=0000 SI=0000 DI=0000 DS=144C ES=143C SS=144C CS=144E IP=0013 NV UP EI PL NZ NA PO NC 144E:0013 E2F6 LOOP000B -pAX=216D BX=0010 CX=0000 DX=0000 SP=0000 BP=0000 SI=0000 DI=0000 DS=144C ES=143C SS=144C CS=144E IP=0015 NV UP EI PL NZ AC PO NC 144E:0015 B8004C MOVAX,4C00 -d ss:0144C:0000 77 65 6C 63 6F 6D 65 20-74 6F 20 6D 61 73 6D 21 welcome to masm!144C:0010 77 65 6C 63 6F 6D 65 20-74 6F 20 6D 61 73 6D 21 welcome to masm!144C:0020 B8 4C 14 8E D8 BB 00 00-B9 08 00 8B 07 89 47 10 .L............G.-pAX=4C00 BX=0010 CX=0000 DX=0000 SP=0000 BP=0000 SI=0000 DI=0000 DS=144C ES=143C SS=144C CS=144E IP=0018 NV UP EI PL NZ AC PO NC 144E:0018 CD21 INT21 -pProgram terminated normally-p

结果1:从结果可以看出，我们达到了目的。

第二种是使用si和di来进行的

源代码2:

assume cs:codesg,ds:datasgdatasg segment db 'welcome to masm!' db '................' datasg endscodesg segment start:mov ax,datasg mov ds,ax mov si,0 mov di,0 mov cx,8h s:mov ax,[si] mov [10h+di],ax add si,2 add di,2 loop s mov ax,4c00h int 21h codesg endsend start  

调试过程2：

-rAX=0000 BX=0000 CX=0040 DX=0000 SP=0000 BP=0000 SI=0000 DI=0000 DS=143C ES=143C SS=144C CS=144E IP=0000 NV UP EI PL NZ NA PO NC 144E:0000 B84C14 MOVAX,144C -u144E:0000 B84C14 MOVAX,144C 144E:0003 8ED8 MOVDS,AX 144E:0005 BE0000 MOVSI,0000 144E:0008 BF0000 MOVDI,0000 144E:000B B90800 MOVCX,0008 144E:000E 8B04 MOVAX,[SI] 144E:0010 894510 MOV[DI+10],AX 144E:0013 83C602 ADDSI,+02 144E:0016 83C702 ADDDI,+02 144E:0019 E2F3 LOOP000E 144E:001B B8004C MOVAX,4C00 144E:001E CD21 INT21 -tAX=144C BX=0000 CX=0040 DX=0000 SP=0000 BP=0000 SI=0000 DI=0000 DS=143C ES=143C SS=144C CS=144E IP=0003 NV UP EI PL NZ NA PO NC 144E:0003 8ED8 MOVDS,AX -tAX=144C BX=0000 CX=0040 DX=0000 SP=0000 BP=0000 SI=0000 DI=0000 DS=144C ES=143C SS=144C CS=144E IP=0005 NV UP EI PL NZ NA PO NC 144E:0005 BE0000 MOVSI,0000 -tAX=144C BX=0000 CX=0040 DX=0000 SP=0000 BP=0000 SI=0000 DI=0000 DS=144C ES=143C SS=144C CS=144E IP=0008 NV UP EI PL NZ NA PO NC 144E:0008 BF0000 MOVDI,0000 -d ds:0144C:0000 77 65 6C 63 6F 6D 65 20-74 6F 20 6D 61 73 6D 21 welcome to masm!144C:0010 2E 2E 2E 2E 2E 2E 2E 2E-2E 2E 2E 2E 2E 2E 2E 2E ................144C:0020 B8 4C 14 8E D8 BE 00 00-BF 00 00 B9 08 00 8B 04 .L..............-pAX=144C BX=0000 CX=0040 DX=0000 SP=0000 BP=0000 SI=0000 DI=0000 DS=144C ES=143C SS=144C CS=144E IP=000B NV UP EI PL NZ NA PO NC 144E:000B B90800 MOVCX,0008 -pAX=144C BX=0000 CX=0008 DX=0000 SP=0000 BP=0000 SI=0000 DI=0000 DS=144C ES=143C SS=144C CS=144E IP=000E NV UP EI PL NZ NA PO NC 144E:000E 8B04 MOVAX,[SI] DS:0000=6577-pAX=6577 BX=0000 CX=0008 DX=0000 SP=0000 BP=0000 SI=0000 DI=0000 DS=144C ES=143C SS=144C CS=144E IP=0010 NV UP EI PL NZ NA PO NC 144E:0010 894510 MOV[DI+10],AX DS:0010=2E2E-pAX=6577 BX=0000 CX=0008 DX=0000 SP=0000 BP=0000 SI=0000 DI=0000 DS=144C ES=143C SS=144C CS=144E IP=0013 NV UP EI PL NZ NA PO NC 144E:0013 83C602 ADDSI,+02 -pAX=6577 BX=0000 CX=0008 DX=0000 SP=0000 BP=0000 SI=0002 DI=0000 DS=144C ES=143C SS=144C CS=144E IP=0016 NV UP EI PL NZ NA PO NC 144E:0016 83C702 ADDDI,+02 -pAX=6577 BX=0000 CX=0008 DX=0000 SP=0000 BP=0000 SI=0002 DI=0002 DS=144C ES=143C SS=144C CS=144E IP=0019 NV UP EI PL NZ NA PO NC 144E:0019 E2F3 LOOP000E -pAX=216D BX=0000 CX=0000 DX=0000 SP=0000 BP=0000 SI=0010 DI=0010 DS=144C ES=143C SS=144C CS=144E IP=001B NV UP EI PL NZ AC PO NC 144E:001B B8004C MOVAX,4C00 -d ds:0144C:0000 77 65 6C 63 6F 6D 65 20-74 6F 20 6D 61 73 6D 21 welcome to masm!144C:0010 77 65 6C 63 6F 6D 65 20-74 6F 20 6D 61 73 6D 21 welcome to masm!144C:0020 B8 4C 14 8E D8 BE 00 00-BF 00 00 B9 08 00 8B 04 .L..............-pAX=4C00 BX=0000 CX=0000 DX=0000 SP=0000 BP=0000 SI=0010 DI=0010 DS=144C ES=143C SS=144C CS=144E IP=001E NV UP EI PL NZ AC PO NC 144E:001E CD21 INT21 -pProgram terminated normally-p

从结果也可以看出达到了目的。