bcd_aaa.asm

来自「汇编语言 参考书 包含作业与答案 从入门到精通 通俗易懂」· 汇编 代码 · 共 53 行

; This example shows the use
; of AAA instruction (ASCII
; Adjust after Addition).
; It is used to add huge
; BCD numbers.

#make_COM#

ORG     100h

; first number '9':
MOV     AH, 09h

; second number '5':
MOV     AL, 05h

; AL = AL + AH =
;    = 09h + 05h = 0Eh
; ('0D' - not BCD form):
ADD     AL, AH

; clear tens byte of BCD
; result:
XOR     AH, AH

; adjust result to BCD form,
; AH = 1, AL = 4  ->  '14'
AAA

; print the result:

; store contents of
; AX register:
MOV     DX, AX

; print first digit:
MOV     AH, 0Eh
; convert to ascii:
OR      DH, 30h
MOV     AL, DH
INT     10h

; print second digit:
; convert to ascii:
OR      DL, 30h
MOV     AL, DL
INT     10h


RET

END