汇编语言第五章1_12习题解

《IBM-PC汇编语言程序设计第二版》部分习题答案(第5章)

清华大学出版社，沈美明、温冬婵编著。

5.1 试编写一个汇编语言程序，要求对键盘输入的小写字母用大写字母显示出来。

.model small

.stack 100H

.code

main proc far

Start:

push dx

push ax

mov ax ,0

input：

mov ah,01H’

int 21H

cmp al,61H

jl lop1

cmp al,7AH

jg lop1

sub al,20H

mov dl,al

mov ah,02H

int 21H

mov dl，20h

mov ah，02h

int 21h

jmp input

lop1:

ret

endp

End start

5.2 编写一个程序，从键盘接受一个小写字母，然后找出它的前导字符和后续字符，再按顺序显示这三个字符。

.model small

.386

.code

MAIN PROC FAR

start:

push ds

push ax

sub ax,ax

input:

mov ah,07H

int 21H

cmpe:

cmp al,20H

JE exit

cmp al,61H

JL input

cmp al,7AH

JG input

print:

sub al,01H

mov dl,al

mov ah,02H

int 21H

add al,01H

mov dl,al

mov ah,02H

int 21H

add al,01H

mov dl,al

mov ah,02H

int 21H

mov dl,0DH ;输出回车 mov ah,02H

int 21H

mov dl,0AH ;输出换行 mov ah,02H

int 21H

jmp input

exit :

ret

MAIN ENDP

END start

5.3 将AX寄存器中的16位数分成4组，每组4位，然后把这四组数分别放在AL、BL、CL、DL中。

.model small

.data

x DB 4 dup(?)

.stack 100H

.code

MAIN PROC FAR

start:

push ds

push ax

push bx

push cx

push dx

mov ax,0h

mov ax,@data

mov ds,ax

mov ax,1234H

mov cx,04H

mov si,00H

lop:

push cx

mov cl,04H

rol ax,cl

push ax

and al,0FH

mov x[si],al

pop ax

pop cx

add si,1

Loop lop

MOV SI,01H

mov al,X[SI]

INC SI

mov bl,X[SI]

INC SI

mov cl,X[SI]

mov dl,[X]

print:

ADD AL，30H

ADD BL，30H

ADD CL，30H

ADD DL，30H

mov ah,02H

int 21H

mov dl,al

mov ah,02H

int 21H

mov dl,bl

mov ah,02H

int 21H

mov dl,cl

mov ah,02H

int 21H

pop dx

pop cx

pop bx

exit:

ret

MAIN ENDP

END start

5.4 编写一个程序，要求比较两个字符串STRING1和STRING2所含字符是否相同，若相同则显示"MATCH"，若不同则显示:"NO MATCH"。

.model small

.data

STRING1 DB 'I must study hard'

Max1 dw $-string1

STRING2 DB 'I must study hard'

Max2 dw $-string2

X DB 'MATCH$'

Y DB 'NO MATCH$'

.stack 100H

.code

main proc far

Start:

push dx

push ax

mov ax,0

mov ax,@data

mov ds,ax

mov es,ax

mov ax,max1

cmp ax,max2

jne nomatch

lea si,STRING1

lea di,STRING2

mov cx,max1

cld

repe cmpsb

cmp cx,00H

je match

nomatch:

lea dx,y

mov ah,09H

int 21H

jmp exit

match:

lea dx,x

mov ah,09H

int 21H

exit:

ret

End start

5.5编写一个程序，要求能从键盘接收一个个位数N，然后响铃N次，（响铃的ASCII为07）。

.model small

.code

main proc far

start:

push ds

push ax

sub ax,ax

input:

mov ah,01H

int 21H

cmp al,20H

je exit

cmp al,30H

jle input

cmp al,3AH

jge input

sub al,30H

mov cx,ax

and cx,0FFH

lop:

mov dl,07H

mov ah,02H

int 21H

loop lop

jmp input

exit :

ret

main endp

end start

5.6编写程序，将一个包含有20个数据的数组M分成两个数组：正数数组P和负数数组N，并分别把这两个数组中的数据个数显示出来。

.model small

.386

.data

M DB 1,2,3,4,5,6,7,8,9,10,-1,-2,-3,-4,-5,-6,-7,-8,-9,-10

P DB 20 dup(?)

N DB 20 dup(?)

.stack 100H

.code

MAIN PROC FAR

start:

PUSH ax

AND ax,0

MOV ax,@data

mov ds,ax

MOV bx,0

MOV si,0

MOV di,0

MOV cx,20D

cmpe :

CMP M[bx],0

JL ifLow ；小于0 hight :

MOV al, M[bx]

MOV P[si],al

inc si

JMP commonContrl ifLow :

MOV al, M[bx]

MOV N[di],al

INC di commonContrl:

INC bx

loop cmpe

mov cx,si

mov si,0

nunp:

mov al,P[si]

call showNumber

inc si

loop nunp

call printCR

mov cx,di

mov di,0

nunn:

mov al,N[di]

call showNumber

inc di

exit: ret

MAIN ENDP

showNumber PROC NEAR

covernum:

push ax

push bx

push cx

push dx

and ax,0ffH

cmp al,0

jnl positive

neg al

mov dl,2DH

mov ah,02H

int 21H

mov ah,0

positive:

cbw

aam

sub cl,cl

mov bl,al

mov al,ah

cbw

aam

mov cl,al

mov dl,ah

add dl,30h

mov ah,2H

int 21h

mov dl,cl

add dl,30h

int 21h

mov dl,bl

add dl,30h

int 21h

mov dl,2cH

int 21H

mov dl,20H

int 21H

pop dx

pop cx

pop bx

pop ax

ret

showNumber ENDP ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

printCR PROC NEAR

mov dl,0aH

mov ah,02H

int 21H

mov dl,0dH

mov ah,02H

int 21H

ret

printCR ENDP

end start

5.7编制一个汇编语言程序，求出首地址为DATA的100D字数组中的最小偶数，并把它放在AX中。

此题根据题意要求应该使用完整汇编格式，因为精简格式也使用DATA....

dataare segment

DATA DW 3322H,4555H,200H,3544H,1245H

num DB ($-DATA)/2

dataare ends

code segment

assume cs:code,ds:dataare

MAIN PROC FAR

start:

push ds

push ax

mov ax,0H

mov ax,dataare

mov ds,ax

mov dx,0H ;偶数数量计数

mov cx,num

mov si,0H

isO:

mov bx,DATA[si]

shr bx,1H

jnc addDX

jmp commonControl

addDX:

ADD dx,1H

cmp dx,1H

je firstAXValue

compare:

mov bx,DATA[si]

cmp bx,ax

jge commonControl

mov ax,bx

commonControl:

ADD si,2H

loop isO

jmp exit

firstAXvalue:

mov ax,DATA[si]

jmp compare

exit:

ret

MAIN ENDP

CODE ENDS

END START

5.9编写一个汇编语言程序，要求从键盘上接收一个四位的十六位进制数，并在终端上显示与它等值的二进制数。

.MODEL SMALL

.386

.STACK100H

.CODE

MAIN proc far

start:

push ds

push ax

mov ax,0

mov cx,4

input:

mov ah,01H int 21H

cmp al,30H jl input

cmp al,39H jle s

cmp al,41H

jl input

cmp al,46H

jle sub1

cmp al,61H jl input

cmp al,66H jle sub2

jmp input

sub1:

sub al,07H jmp s

sub2:

sub al,27H s:

sub al,30H

add dl,al

cmp cx,1H

je f

PUSH CX

MOV CL，04H rol dx,CL POP CX

f:

loop input exit:

call print

ret

main endp print proc near

p:

rol dx,01H

push dx

and dL,01H

add dL,30H

mov ah,02H

int 21H

MOV DL，0DH

INT 21H

pop dx

loop p

ret

print endp

end start

5.10设有一段英文，其变量字符名为ENG，并以$字符结束。试编写一程序，查对单词SUN在该文中的出现次数，并以格式"SUN XXXX"显示出次数。

.model small

.386

.data

ENG db 'SUN's SUN JAVA',24H ;24H = $

MESSAGE db 'SUN:','$'

.stack 100H

.code

MAIN PROC FAR

start:

PUSH DS

PUSH AX

AND AX,0

MOV AX,@data

MOV DS,AX

MOV AX,0H

MOV SI,01H

subSI1:

SUB SI,01H

subSI2:

SUB SI,01H

compareS:

MOV DL,ENG[SI]

CMP DL,24H

JE print

CMP DL,53H ；S的ASCII码

JNE compareS

compareU:

ADD SI,01H

MOV DL,ENG[SI]

CMP DL,55H ；U的ASCII码

JNE subSI2

compareN:

ADD SI,01H

MOV DL,ENG[SI]

CMP DL,4EH ; N的ASCII码

JNE subSI1

INC AX

JMP compareS

print:

LEA DX,MESSAGE

PUSH AX

MOV AH,09H

INT 21H

POP AX

call showNumber

exit:

ret

MAIN ENDP

;;;;;;;;;;;;;;;;;注意，ShowNumber这个子过程仅能显示al中99以内的数;;;;;;;;;;;;;;;;

showNumber PROC NEAR

covernum:

DAA

MOV dx,ax

mov bl,02H

show:

MOV cl,04H

ROL dl,cl

push dx

ADD dl,30H

MOV ah,02H

int 21H

pop dx

dec bl

jnz show

ret

showNumber ENDP

END start

5.11从键盘输入一系列以$为结束符的字符串，然后对其中的非数字字符计数，并显示出计数结果。

.model small

.386

.code

MAIN PROC FAR

start:

push ds

push ax

mov ax,0

mov cx,0

input:

mov ah,1H

int 21H

compare:

cmp al,24H

je print

cmp al,30H

jl addCount

cmp al,39H

jle input

addCount:

add ax,1H

jmp input

print:

call showNumber

exit: ret

MAIN ENDP

;;;;;;注意，ShowNumber这个子过程仅能显示al中99以内的数;;;;;

showNumber PROC NEAR

covernum:

DAA

MOV dx,ax

MOV bl,2H

show:

mov cl,04H

ROL dl,cl

push dx

AND dl,0fH

ADD dl,30H

MOV ah,02H

int 21H

pop dx

dec bl

jnz show

ret

showNumber ENDP

END start

5.12 有一个首地址为MEM的100D字数组，试编制程序删除数组中所有为零的项，并将后续项向前压缩，最后将数组的剩余部分补上零。

.model small

.386

.stack 100H

.data

mem dw

12,0,0,0,0,0,1,2,3,6,4,7,8,2,1,0,0,54,5,0,2,4,7,8,0,5,6,2,1,4,8,5,1,45

,7,5,1,2,0,2,4,0,2,54,0,12,0,0,0,0,0,1,2,3,6,4,7,8,2,1,0,0,54,5,0,2,4,

7,8,0,5,6,2,1,4,8,5,1,45,7,5,1,2,0,2,4,0,2,54,0,45,7,5,1,2,0,2,4,0,2

.code

MAIN PROC FAR

start:

push ds

push ax

and ax,0

mov ax,@data

mov ds,ax ;----------------------

mov ax,0H

mov bx,64H

mov cx,64H

mov si,0FFFEH

repeat:

ADD si,2H

cmp MEM[si],0H

JE calls

loop repeat

calls:

INC ax

call sort

cmp ax,1H

JE lastValue

DEC cx

jmp repeat

exit :

ret

lastValue:

mov mem[bx],0H

DEC cx

jmp repeat

MAIN ENDP

sort PROC NEAR ;前后数据交换，直到最后 push cx

push si

sub si,2H

s:

add si,2H

mov dx,mem[si+2]

mov mem[si],dx

loop s

return:

pop si

pop cx

ret

sort ENDP

END start