【X86組語】作業二

作業二，0~99兩數字加減法

;;;; 程式說明 ;;;;
;; 使用者輸入一算數
GETCHAR     MACRO   char
           push    ax
           mov     ah,01h
           int     21h
           mov     char,al
           pop     ax
           ENDM
PUTCHAR     MACRO   char
           push    dx
           push    ax
           mov     dl,char

           mov     ah,02h
           int     21h
           pop     ax
           pop     dx
           ENDM
END_PROCESS MACRO
           mov     ah,4ch
           int     21h
           ENDM

.MODEL      SMALL
.DATA
values      db      2 dup(?)

operator    db      1 dup(?)

.STACK

.CODE
main_pro    proc    far

           mov     dl,3
count_loop: mov     si,0
keyin_loop: GETCHAR bl
           cmp     bl,'+'

           je      go_1
           cmp     bl,'-'
           jne     continue
go_1:       cmp     si,0
           je      invalid
           mov     [operator],bl
           jmp     keyin_loop
go_2:       mov     [operator],bl
           jmp     finish
continue:   call    check_num
           mov     cl,bl
           GETCHAR bl
           cmp     bl,'+'

           je      go_2
           cmp     bl,'-'
           je      go_2
           mov     al,10
           mul     cl
           mov     cl,al
           call    check_num
           add     cl,bl
finish:     mov     [values+si],cl
           inc     si
           cmp     si,2
           jne     keyin_loop

           mov     al,[values]
           mov     bl,[values+1]
           mov     cl,[operator]
           cmp     cl,'-'
           jne     do_add
           sub     al,bl
           call    print_ans
           jmp     ok
do_add:     add     al,bl
           call    print_ans
ok:         dec     dl
           jnz     count_loop

           END_PROCESS
main_pro    endp



check_num   proc    far
           cmp     bl,'0'

           jl      invalid
           cmp     bl,'9'
           jg      invalid
           sub     bl,'0'
           ret
check_num   endp

print_ans   proc    far
           PUTCHAR '='
           cmp     al,100
           jb      ignore_h
           PUTCHAR '1'

           sub     al,100
ignore_h:   mov     cl,10
           div     cl
           add     al,'0'
           add     ah,'0'
           PUTCHAR al
           PUTCHAR ah
           call    cr_lf
           ret
print_ans   endp


cr_lf       proc    far
           push    ax
           push    dx
           mov     ah,2
           mov     dl,0dh
           int     21h
           mov     dl,0ah
           int     21h
           pop     dx
           pop     ax
           ret
cr_lf       endp


invalid:    PUTCHAR '!'
           END_PROCESS
END