START: MOV AX,@DATA MOV DS,AX MOV AL,DAT CMP AL,0 JZ ZERO JNS POSI MOV DL,’-’ DISPLAY

STOP: MOV AX,4C00H INT 21H

ZERO: MOV DL,’0’ DISPLAY JMP STOP

POSI: MOV DL,’+’ DISPLAY JMP STOP END START

4.23答： .MODEL SMALL .CODE

START: XOR BX,0 MOV CX,200 MOV DX,1

AGN: ADD BX,DX; 求和 INC DX INC DX LOOP AGN CALL BTOH MOV AX,4C00H INT 21H BTOH PROC MOV CL,4

MOV DL,BH;最高位 SHR DL,CL CMP DL,0AH JC N1

ADD DL,7

N1: ADD DL,30H MOV AH,2 INT 21H

MOV DL,BH;次高位 AND DL,0FH CMP DL,0AH JC N2 ADD DL,7

N2: ADD DL,30H MOV AH,2 INT 21H

MOV DL,BL;次低位 SHR DL,CL CMP DL,0AH JC N3 ADD DL,7

N3: ADD DL,30H MOV AH,2 INT 21H

MOV DL,BL;最低位 AND DL,0FH CMP DL,0AH JC N4 ADD DL,7

N4: ADD DL,30H MOV AH,2 INT 21H RET

BTOH ENDP END START

4.24答：

.MODEL SMALL .DATA

DAT DB ??;准备100个数 RESULT DW ?

.CODE

START: MOV AX,@DATA

MOV DS,AX MOV CX,99 LEA SI,DAT MOV DL,[SI] MOV DH,DL INC SI MOV BX,SI

AGN1: CMP DH,[SI];求出最大值

JNB NEXT1 MOV DH,[SI] NEXT1: INC SI

LOOP AGN1 MOV CX,99

AGN2: CMP DL,[BX];求出最小值

JB NEXT2 MOV DL,[BX] NEXT2: INC BX

LOOP AGN2 XOR AX,AX;求和 ADD DH,DL MOV AL,DH ADC AX,0 MOV RESULT,AX ;int 3

MOV AX,4C00H INT 21H END START 4.25答： DPLY0 MACRO MOV DL,30H MOV AH,2 INT 21H ENDM

DPLY1 MACRO

MOV DL,31H MOV AH,2 INT 21H ENDM

.MODEL SMALL

.DATA

CNT DW 0AB3FH;准备数

.CODE

START: MOV AX,@DATA

MOV DS,AX MOV BX,CNT MOV CX,16 AGN: SHL BX,1 JC NEXT DPLY0 LOOP AGN NEXT: DPLY1 LOOP AGN MOV AX,4C00H INT 21H END START

4.26答：

.MODEL SMALL .DATA

STRG DB ??;准备字符串

.CODE

START: MOV AX,@DATA

MOV DS,AX LEA SI,STRG MOV CX,100

AGN: MOV AL,[SI] CMP AL,61H JB N1 CMP AL,7AH JA N1 SUB AL,20H