3.asm

设有10个学生的成绩分别为56、69、84、82、73、88、99、63、100和80分。试编制程序分别统计低于60分、60～69分、70～79分、80～89分、90～99分及100分的人数存放到s5

datarea   segment                     ;define data segment
  grade   dw          56,69,84,82,73,88,99,63,100,80
  s5      dw          0
  s6      dw          0
  s7      dw          0
  s8      dw          0
  s9      dw          0
  s10     dw          0
datarea  ends
;************************************
prognam segment                       ;define code segment
;----------------------------
main      proc      far               ; main part of program
assume  cs:prognam, ds:datarea
start:                                ; starting execution address
; set up stack for return
         push     ds                  ; save old data segment
         sub      ax,ax               ; put zero in AX
         push     ax                  ; save it on stack
; set DS register to current data segment
         mov      ax,datarea          ; datarea segment addr
         mov      ds,ax               ; into DS register
; MAIN PART OF PROGRAM GOES HERE
         mov      s5, 0               ; initialize counter
         mov      s6, 0
         mov      s7, 0
         mov      s8, 0
         mov      s9, 0
         mov      s10, 0
         mov      cx, 10              ; initialize loop count value
         mov      bx, offset grade      ; initialize first addr
compare:
         mov      ax, [bx]             ; get a result
         cmp      ax, 60               ; <60?
         jl        five
         cmp     ax, 70                ; <70?
         jl       six
         cmp     ax, 80                ; <80?
         jl       seven
         cmp     ax, 90                ; <90?
         jl       eight
         cmp     ax, 100               ; =100?
         jne      nine
         inc      s10
         jmp     short change_addr 
  nine:  inc       s9
         jmp     short change_addr 
  eight:  inc      s8
         jmp     short change_addr
  seven:  inc      s7
         jmp     short change_addr
  six:    inc       s6
         jmp     short change_addr
  five:   inc       s5
change_addr:
         add     bx, 2
         loop    compare
         ret                           ; return to DOS
main     endp                         ; end of main part of program
; ------------------------------
prognam  ends
;***************************
         end     start                 ; end assembly