MOV SI,0 ；将DX 转换成十进制数，再转换成ASCII 码—>NUM MOV AX,DX MOV DX,0 MOV BX,10 D2: DIV BX ADD DL,30H
MOV NUM[SI],DL INC SI CMP AX,0 JZ EXIT MOV DX,0 JMP D2
EXIT: MOV DL,0AH ；显示十进制数 MOV AH,2 INT 21H
MOV DL,0DH INT 21H D3: DEC SI
MOV DL,NUM[SI] MOV AH,2 INT 21H JNZ D3
MOV AH,4CH INT 21H CODE ENDS END START
14. 将AX 中的无符号二进制数转换成ASCII 字符串表示的十进制数。
答：将13 题输入过程和输出过程去掉即得。 DATA SEGMENT
NUM DB 10 DUP(?) ；转换后ASCII 码按倒序存放于NUM DATA ENDS
CODE SEGMENT
ASSUME CS:CODE,DS:DATA START: MOV AX,DATA MOV DS,AX MOV AX, ×××× ；无符号二进制数
MOV SI,0 ；将AX 转换成十进制数，再转换成ASCII 码—>NUM MOV DX,0 MOV BX,10 D2: DIV BX ADD DL,30H
MOV NUM[SI],DL INC SI CMP AX,0 JZ EXIT MOV DX,0 JMP D2
EXIT: MOV AH,4CH INT 21H CODE ENDS END START
15. 从键盘输入20 个有符号数，将它们排序并在屏幕上显示。答：DATA SEGMENT
NUM DW 20 DUP(?) ；存放20 个有符号数
ASC DB 10 DUP(?) ；输出时暂时保存每一个数的ASCII 码 DATA ENDS
CODE SEGMENT
ASSUME CS:CODE,DS:DATA START: MOV AX,DATA MOV DS,AX MOV CX,20 MOV BX,10 MOV SI,0 MOV BP,0
BEGIN: MOV DX,0 ；输入20 个有符号数（十进制），并 A1: MOV AH,1 ；转化为二进制数存放于NUM 数组 INT 21H
CMP AL,' ' ；判断是否空格 JZ A2
CMP AL,0DH ；是否回车符 JZ A2
CMP AL,'-' ；是否?-? JZ A3 JMP A4
A3: MOV BP,1 JMP A1
A4: PUSH AX MOV AX,DX MUL BX MOV DX,AX POP AX
SUB AL,30H MOV AH,0 ADD DX,AX JMP A1
A2: CMP BP,1 JNZ A5
NEG DX ；若为负数，则取负 A5: MOV NUM[SI],DX MOV BP,0 ADD SI,2 LOOP BEGIN
MOV DL,0DH ；回车换行 MOV AH,2 INT 21H
MOV DL,0AH INT 21H
MOV BX,0 ；对20 个有符号数按由小到大顺序排序
MOV CX,19 ；采用冒泡法，排序后依然存放于NUM 数组 L1: MOV DX,CX
L2: MOV AX,NUM[BX] CMP AX,NUM[BX+2] JLE CONT1
XCHG AX,NUM[BX+2] MOV NUM[BX],AX CONT1: ADD BX,2 LOOP L2 MOV CX,DX MOV BX,0 LOOP L1
MOV CX,20 ；将20 个有符号数（二进制）转换为十进制数MOV SI,0 ；再转换为ASCII 码并输出屏幕 D1: MOV AX,NUM[SI] ADD SI,2
TEST AX,1000H JZ D4 PUSH AX MOV DL,'-' MOV AH,2 INT 21H POP AX NEG AX
D4: MOV DI,0 MOV DX,0 MOV BX,10 D2: DIV BX ADD DL,30H
MOV ASC[DI],DL INC DI
CMP AX,0 JZ D3
MOV DX,0 JMP D2
D3: MOV DL,ASC[DI-1] MOV AH,2 INT 21H DEC DI JNZ D3 MOV DL,' ' MOV AH,2 INT 21H LOOP D1
MOV AH,4CH ；返回DOS INT 21H CODE ENDS END START
16. 编写多字节有符号数的加法程序，从键盘接收两个加数，在屏幕上显示结果。 答：DATA SEGMENT
STRING1 DB 'INPUT FIRST NUM(HEX):',0DH,0AH,'$' STRING2 DB 'INPUT SECOND NUM(HEX):',0DH,0AH,'$' STRING3 DB 'THE RESULT IS(HEX):',0DH,0AH,'$' NUM1 DW 0,0 ；存放加数1 NUM2 DW 0,0 ；存放加数2 RESULT DB 0,0,0,0 ；存放结果 DATA ENDS
CODE SEGMENT
ASSUME CS:CODE,DS:DATA START: MOV AX,DATA MOV DS,AX
LEA DX,STRING1 ；输入第一个加数（4 位十六进制数） MOV AH,9 INT 21H MOV SI,2 MOV CX,8
CONT: PUSH CX CMP CX,4 JNZ B1 SUB SI,2
B1: MOV CL,4 SHL NUM1[SI],CL C1: MOV AH,1 INT 21H
CMP AL,'0' JB C1
CMP AL,'F' JA C1
CMP AL,'A' JB A1 SUB AL,7
A1: SUB AL,30H MOV AH,0
ADD NUM1[SI],AX POP CX
LOOP CONT
MOV DL,0DH ；回车换行 MOV AH,2 INT 21H
MOV DL,0AH INT 21H
LEA DX,STRING2 ；输入第二个加数（4 位十六进制数）MOV AH,9 INT 21H MOV SI,2 MOV CX,8
CONT1: PUSH CX CMP CX,4 JNZ B2 SUB SI,2
B2: MOV CL,4 SHL NUM2[SI],CL C2: MOV AH,1 INT 21H CMP AL,'0' JB C2
CMP AL,'F' JA C2
CMP AL,'A' JB A2 SUB AL,7
A2: SUB AL,30H MOV AH,0
ADD NUM2[SI],AX POP CX
LOOP CONT1
MOV DL,0DH ；回车换行 MOV AH,2