这个是实现（w+xy-z）/x编译时说除法溢出，不懂怎么改
DATA SEGMENT
X DB 01H
Y DB 04H
Z DB 04H
W DB 02H
RESULT DB ?
DATA ENDS
CODE SEGMENT
ASSUME CS:CODE,DS:DATA
START: MOV AX,DATA
MOV DS,AX
MOV AL,X
IMUL Y
MOV CX,AX
MOV AL,W
CBW
ADD AX,CX
MOV BX,Z
SUB AX,BX
IDIV X
MOV RESULT,AH
MOV RESULT+1,AL
MOV AH,4CH
INT 21H
CODE ENDS
END START

[最优解释]

DATA   SEGMENT
X      DB 01H
Y      DB 04H
Z      DB 04H
W      DB 02H
RESULT DB ?
DATA   ENDS
CODE   SEGMENT
       ASSUME CS:CODE,DS:DATA
START:
MOV  AX,DATA
       MOV  DS,AX
       MOV  AL,X
       IMUL Y
       MOV  CX,AX
       MOV  AL,W
       CBW
       ADD  AX,CX
       xorbx,bx
       MOV  bl, Z
       SUB  AX,BX
       IDIV X
       MOV  RESULT,AH
       MOV  RESULT+1,AL
       MOV  AH,4CH
       INT  21H
CODE   ENDS
END START