Question

用汇编语言编程

内存中以FIRST和SECOND开始的单元中分别存放着两个16位组合的十进制(BCD码)数,低位在前。编程序求这两个数的组合的十进制和,并存到以THIRD开始的单元。

要求此程序能在masm5.0环境里运行

Answer 1

SSEG SEGMENT STACK
STK DB 20 DUP(?)
SSEG ENDS
DSEG SEGMENT
FIRST DB 56H,23H ；设FIRST存放着十进制数2356
SECOND DB 45H,31H ；设SECOND存放着十进制数3145
THIRD DB 0,0,0

DSEG ENDS
CSEG SEGMENT
ASSUME CS:CSEG,DS:DSEG,SS:SSEG

START: MOV AX,DSEG
MOV DS,AX

MOV AL,FIRST
ADD AL,SECOND
DAA
MOV THIRD,AL

MOV AL,FIRST+1
ADC AL,SECOND+1
DAA
MOV THIRD+1,AL

JNC L1

MOV AL,01H
MOV THIRD+2,AL

L1: MOV AH,4CH
INT 21H

CSEG ENDS
END START