mov r0,Y
cjne r0,#50,c0
c0:
jc X_1
mov X,#01h
ajmp Finish
X_1:
mov X,#81h ;最高位表示符号位,“1”表示负数
Finish:
ret
或者用subb
mov a,Y
clr c
subb a,#50
jc X_1
mov X,#01h
ajmp Finish
DATA SEGMENT
Y DB 56
X DB ?
DATA ENDS
CODE SEGMENT
ASSUME DS:DATA,CS:CODE
START:
MOV AX,DATA
MOV DS,AX
CMP Y,50
JAE GREAT
MOV X,-1
JMP FINISH
GREAT:
MOV X,1
FINISH:
MOV AX,4C00H
INT 21
CODE ENDS
END START