Binary search program for 8085

Answer 1

Res db " position",13,10,"$"

msg2 db 'key not found!!!!!!!!!!!!!. $'

.code

mov ax,@data

mov ds,ax

mov bx,00

mov dx,len

mov cx,key

again:cmp bx,dx

ja fail

mov ax,bx

add ax,dx

shr ax,1

mov si,ax

add si,si

cmp cx,arr[si]

jae big

dec ax

mov dx,ax

jmp again

big:je success

inc ax

mov bx,ax

jmp again

success:add al,01

add al,'0'

mov res,al

lea dx,msg1

jmp disp

fail:lea dx,msg2

disp:mov ah,09h

int 21h

mov ah,4ch

Answer 2

To do a binary search on a list of numbers, the algorithm is

1. Initialize two pointers, low and high, to point to the first (low) and last (high) elements of the list. (The list must be in ascending order.)
2. Start of loop, loop until low is greater than high...
3. Initialize pointer, mid, to be (low + high) / 2.
4. If mid points to item desired, stop - you have found the item.
5. If mid points to item above search term, set high to mid - 1 and loop.
6. otherwise set low to mid + 1 and loop.
7. At this point, you know the search term is not found. You also know that low points to where it would need to be inserted into the list.