问题
how can i display index number of the element which i have found? i have found out the maximum element from the array and now I want to print the index of the element which I have found how to proceed?
i want to find the element of the largest number which i found in the array according to the below logic ?
Data Segment
msg db 0dh,0ah,"Please enter the length of the array: $"
msg1 db 0dh,0ah,"Enter a number: $"
newl db 0dh,0ah," $"
res db 0dh,0ah,"The maximum is: $"
len db ?
max db ?
Data ends
Code Segment
assume CS:Code,DS:Data
Start:
mov ax,Data
mov DS,ax
mov dx,offset msg
mov ah,09h
int 21h
call Accept
mov len,bl
mov cl,bl
mov ch,00h
mov di,1000h
back: mov dx,offset msg1
mov ah,09h
int 21h
call Accept
mov [di],bl
inc di
loop back
mov di,1000h
mov cl,len
mov ch,00h
mov dx,offset newl
mov ah,09h
int 21h
mov al,[di]
mov max,al
chk: mov bl,max
mov al,[di]
cmp bl,al
jc a
mov max,bl
jmp b
a: mov max,al
b: inc di
loop chk
mov dx,offset res
mov ah,09h
int 21h
mov bl,max
call DispNum
mov ah,4ch
int 21h
Accept proc
mov ah,01h
int 21h
call AsciiToHex
rol al,4
mov bl,al
mov ah,01h
int 21h
call AsciiToHex
add bl,al
ret
endp
DispNum proc
mov dl,bl
and dl,0f0h
ror dl,4
call HexToAscii
mov ah,02h
int 21h
mov dl,bl
and dl,0fh
call HexToAscii
mov ah,02h
int 21h
endp
AsciiToHex proc
cmp al,41h
jc sk
sub al,07h
sk: sub al,30h
ret
endp
HexToAscii proc
cmp dl,0ah
jc sk2
add dl,07h
sk2: add dl,30h
ret
endp
Code ends
end Start
回答1:
You can find a very, very similar answer here How bizarre that one deals with the maximum and the other deals with the minimum...
mov di,1000h
Because in your 2 hexdigits input routine the biggest value that the user can type is "FF" (255), you could reserve a buffer of that size in your program's data section instead of just trusting that the offset address 1000h will not overlap with anything important in memory.
Data Segment
buf db 256 dup (0)
msg db 0dh,0ah,"Please enter the length of the array: $"
...
To tackle the task of getting the index of the array element where the maximum is located, you can save the current value of the address in DI in an extra register like SI and update that each time the code stumbles upon a bigger value:
...
mov di, offset buf
mov al, [di]
mov max, al
mov si, di ; Address of the first chosen maximum
chk:
mov al, [di]
cmp al, max
jbe a
mov max, al ; Bigger than anything before
mov si, di ; Remember the address of the newest maximum
a:
inc di
loop chk
After this code the index that you're looking for is obtained from subtracting the start of the array from the address of where the maximum was found:
sub si, offset buf ; The index of the maximum
With introducing that SI address comes the opportunity of no longer needing the separate max variable:
...
mov di, offset buf
mov si, di ; Address of the first chosen maximum
chk:
mov al, [di]
cmp al, [si] ; At [si] is the current maximum
jbe a
mov si, di ; Remember the address of the newest maximum
a:
inc di
dec cx
jnz chk
;;; mov al, [si] ; The maximum should you need it
sub si, offset buf ; The index of the maximum
Please note that I've removed the slower loop chk instruction and replaced it by the pair dec cx jnz chk.
来源：https://stackoverflow.com/questions/65121872/how-to-show-the-index-of-element-found-in-tasm-program