.model small
.stack 100h
.data
    a dt ?
    b dt ?
    c dt ?
    str1 db 13,"Enter a = ",'$'
    str2 db 13,"b = ",'$'
    str3 db 13,"c = ",'$'
    length dw 0
    after_poin dw 0
    fminus dw 0

.code

read_fun PROC
    mov ax, 0
    mov length, ax
    mov after_poin, ax
    mov fminus, ax

cin:
    mov ah, 08h
    int 21h

    cmp al, '0'
    jl next                       ;<
    cmp al, '9'
    jg next                       ;>
    inc length

    mov ax, '0'
    sub al, ax
    push al

    mov ax, 0
    cmp after_poin, ax
    je read                       ;=
    inc after_poin

read:


next:
    cmp al, '-'
    je minus
    cmp al, 8
    je bsckspace
    cmp al, '.'
    je p


bsckspace:
    mov ax, 1
    cmp length, ax
    je delete_minus

    mov ax, 0
    cmp length, ax
    jg out

    mov ax, 1
    cmp after_poin, ax
    je del_poin

del_poin:
    mov ax, 0
    mov after_poin, ax

delete_minus:
    mov ax, 0
    mov fminus, ax

out:
    pop al
p:
    mov ax, 0
    cmp fminus, ax
    jge check                    ; >=

    mov ax, 2
    cmp length, ax
    jge write_point

    mov ax, 0
    cmp after_poin, ax
    jne cin                        ;!=
    inc after_poin

    mov ah, 02h
    mov dl, '.'
    int 21h

    jmp cin

check:
    mov ax, 1
    cmp length, ax
    je write_point
    jmp cin

write_point:
    inc after_poin
    inc length
    mov ah, 02h
    mov dl, '.'
    int 21h

    jmp cin

minus:
    mov ax, 0
    cmp fminus, ax
    jmp cin
    mov ax, 1
    mov fminus, ax


    mov ah, 02h
    mov dl, '-'
    int 21h

    jmp cin

    ret
read_fun  endp

count_x PROC

    ret
count_x endp

output PROC

    ret
output endp

start:
    mov ax, @data
    mov ds, ax
    mov es, ax

    mov ah, 09h
    mov dx, offset str1
    int 21h


   call read_fun


    mov ax, 4c00h
    int 21h
end start