samples/rek-gcd-input.asm

   1 .model      small
   2 ASSUME DS:data
   3 ;recursive version of GCD, input from terminal
   4 data segment
   5   strNZD db "        "
   6   tempStr db "        "
   7   prompt  db "num?$"
   8   promptr db "RES $"
   9   m     dw  0
  10   n     dw  0
  11 data ends
  12 ;#macros-removed-from-listing
  13
  14 .code
  15
  16 start:
  17     mov ax,@data
  18     mov ds,ax
  19     print_str prompt
  20     read_num m
  21     print_new_line
  22     print_str prompt
  23     read_num n
  24     print_new_line
  25
  26     push n
  27     push m
  28     call gcd
  29     pop n
  30     print_str promptr
  31         print_num n
  32 ; print out a result
  33     end_execution
  34
  35
  36 ;volatile procedure, ruins ax,bx,cx
  37 gcd proc
  38         ;get params
  39         pop ax
  40         pop bx
  41         cmp ax,bx
  42         je endequal
  43         ja greatera
  44         ;ensure ax is greater
  45         xchg ax,bx
  46 greatera:
  47         sub ax,bx
  48         push bx
  49         push ax
  50         call gcd
  51         pop ax;result
  52
  53 endequal:
  54         push ax; result
  55         ret
  56 gcd endp
  57
  58 .stack
  59 end start