a4-1'.asm

一些微机接口的例子

;A4-1'.asm
;二进制双精度加法运算(使用32位寄存器)

.386
STACK1  SEGMENT STACK
         DW 256 DUP(?)
STACK1  ENDS

DATA SEGMENT	USE16
MES1	DB	'The result is:$'
X	    DD 	1565A0H
Y	    DD 	21B79EH
DATA	ENDS

CODE 	SEGMENT	USE16
	ASSUME CS:CODE,DS:DATA

START: MOV 	AX,DATA
       MOV 	DS,AX

	   MOV	DX,OFFSET MES1
	   MOV	AH,09H
	   INT	21H
	   MOV	SI,OFFSET X
	   MOV 	EAX,[SI]
	   MOV	SI,OFFSET Y
	   ADD	EAX,[SI]
	   PUSH	AX
	   SHR	EAX,16
	   CALL	SHWORD	
	   POP	AX
	   CALL	SHWORD

	   MOV	AX,4C00H
	   INT	21H

SHWORD	PROC	NEAR
	   MOV	BL,AH
	   CALL	SHOW
	   MOV	BL,AL
	   CALL	SHOW
	   RET	
	   ENDP
		
SHOW	PROC	NEAR
	   PUSH	AX
	   PUSH	DX
	   MOV	AL,BL
	   AND	AL,0F0H			;取高4位
	   SHR	AL,4
	   CMP	AL,0AH			;是否是A以上的数
	   JB	C2		
	   ADD	AL,07H		
C2:	   ADD	AL,30H		
	   MOV	DL,AL			;show character 
	   MOV	AH,02H
	   INT	21H
	   MOV	AL,BL
	   AND	AL,0FH			;取低4位
	   CMP	AL,0AH
	   JB	C3
	   ADD 	AL,07H
C3:	   ADD	AL,30H
	   MOV	DL,AL			;show character 
	   MOV	AH,02H
	   INT	21H
	   POP	DX
	   POP	AX
	   RET
	   ENDP	
CODE ENDS
       END START