8259中断实时时钟.doc

DATAS SEGMENT
TIME DB 39H,00H,35H,00H,3AH,00H,39H,00H,35H,00H,3AH,00H,31H,00H,31H
DATAS ENDS
STACKS SEGMENT
DB 100 DUP(?)
STACKS ENDS
CODES SEGMENT
ASSUME DS:DATAS,SS:STACKS,CS:CODES

START:
MOV AX,STACKS
MOV SS,AX
MOV AH,35H
MOV AL,1CH
INT 21H
PUSH ES
PUSH BX
STI
MOV AX,SEG T
MOV DS,AX
MOV DX,OFFSET T
MOV AL,1CH
MOV AH,25H
INT 21H

MOV AL,13H
OUT 20H,AL

MOV AL,08H
OUT 21H,AL
MOV AL,01H
OUT 21H,AL
MOV AL,0FEH
OUT 21H,AL
MOV AL,36H
OUT 43H,AL
MOV AX,0000H
OUT 40H,AL
MOV AL,AH
OUT 40H,AL

L: HLT
JMP L
POP DX
POP AX
MOV DS,AX
MOV AH,25H
MOV AL,1CH
INT 21H
MOV AH,4CH
INT 21H

T PROC NEAR
MOV AX,DATAS
MOV DS,AX
MOV SI,OFFSET TIME
PUSH SI
INC CL
CMP CL,12H
JB S
MOV CL,00H
ADD [SI],01H
CMP [SI],3AH
JB S
MOV [SI],30H
ADD [SI+2],01H
CMP [SI+2],36H
JB S
MOV [SI+2],30H
ADD [SI+6],01H
CMP [SI+6],3AH
JB S
MOV [SI+6],30H
ADD [SI+8],01H
CMP [SI+8],36H
JB S
MOV [SI+8],30H
ADD [SI+0CH],01H
MOV BL,[SI+0CH]
MOV BH,[SI+0EH]
CMP BX,3132H
JAE E
CMP [SI+0CH],3AH
JB S
MOV [SI+0CH],30H
ADD [SI+0EH],01H
JMP S
E: MOV [SI+0EH],30H
MOV [SI+0CH],30H
S: ADD SI,0EH
MOV CH,0FH
Q: MOV DL,[SI]
MOV AH,02H
INT 21H
DEC SI
DEC CH
CMP CH,00H
JNZ Q
POP SI
MOV DL,0DH
MOV AH,02H
INT 21H
MOV AL,20H
OUT 20H,AL

IRET

T ENDP
CODES ENDS
END START