我想用汇编添加两个 30 位数字。如您所知,在 8086 中我们不能添加两个 30 位数字。所以我必须用字符串来做。并使用 AAA 命令将结果放入 sum 变量中,最后检查我们是否执行过,但主要问题是 sum 的结果不正确。它给了我 59427532 加上这 668399 + 759133 的总和。
你能告诉我确切的问题在哪里吗?
.model small
.stack 64
.data
max1 db 30
acc1 db ?
num1 db 30 dup('0')
max2 db 30
acc2 db ?
num2 db 30
sum db 31 dup('0'),'$'
.code
start:
mov ax,@data
mov ds, Ax
mov ah,0ah
lea dx, max1 ;take max 1 and length store it to acc1
int 21h
mov ah,0ah
lea dx,max2 ;take max2 and length store it to acc2
int 21h
mov cl,acc1 ;check if they are equal
cmp cl,acc2
jne exit
mov ch,0 ;make sure our cx is the length of our string
clc
mov si,cx ;set the length for index the char
dec si
l1:
mov al,num1[si] ;sum two hex number
adc al,num2[si] ;add with carry flag
aaa ;seperate carry and hex number and store it into al
pushf
add al,30h ;convert it to ascii again
mov sum[si+2],al ;because of dec si we have to step
popf
dec si
loop l1
jne print
mov sum,31h ; if we have carry flag add to sum otherwise jumpt print
print:
mov ah,09h ;the main problem is here shows the result
lea dx,sum
int 21h
exit:
mov ax,4c00h
int 21h
end start