chp3_26b.asm

关于8086汇编的一些作业程序

stack segment stack'stack'
      dw 32 dup(?)
stack ends
data segment
IBF DB 5,0,5 DUP(0)
OBF DB 9 DUP(0)
data ends
code segment
begin proc far
      assume ss:stack,cs:code,ds:data
      push ds
      sub ax,ax
      push ax
      mov ax,data
      mov ds,ax
      MOV DX,OFFSET IBF
      MOV AH,10
      INT 21H
      MOV BX,1
      MOV CH,IBF[BX]
      MOV CL,4
      XOR AX,AX
AGAIN:INC BX
      SUB IBF[BX],30H
      CMP IBF[BX],0AH
      JB NS7
      SUB IBF[BX],7
NS7:  SHL AX,CL 
      OR AL,IBF[BX]
      DEC CH
      JNZ AGAIN
      AND AH,AH
      JNZ NAP
      CBW
NAP:  MOV BX,OFFSET OBF+8
      MOV BYTE PTR [BX],'$'  
      MOV CX,10
      AND AX,AX
      PUSHF
      JNS NNEG
      NEG AX
NNEG: AND AX,AX
      JZ JOUT
      MOV DX,0
      DEC BX
      DIV CX
      ADD DL,30H
      MOV [BX],DL
      JMP NNEG
JOUT: POPF
      JNS PLUS
      DEC BX
      MOV BYTE PTR [BX],'-'
PLUS: DEC BX
      MOV BYTE PTR [BX],'='
      DEC BX
      MOV BYTE PTR [BX],0AH
      MOV DX,BX
      MOV AH,9
      INT 21H
      ret
begin endp
code ends
     end begin