exp91.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 61 行

CODE     SEGMENT  PARA
         ASSUME CS:CODE,DS:CODE

NEW_INTn        PROC    FAR
                PUSH    AX
                PUSH    BX
                PUSH    CX
                PUSH    DX
                PUSH    SI
                PUSH    DI
                PUSH    BP
                PUSH    DS
                PUSH    ES
                STI

                JMP     START
OLD_INTn        DD      ?
START:          NOP
                NOP

                NOP
RETURN:         CLI
                POP     ES
                POP     DS
                POP     BP
                POP     DI
                POP     SI
                POP     DX
                POP     CX
                POP     BX
                POP     AX
                IRET
NEW_INTn        ENDP

H_LEN           EQU     $-NEW_INTn

MAIN            PROC    FAR
                MOV     AX,CS
                MOV     DS,AX

                MOV     AH,35H
                MOV     AL,9cH            ;INT VECTOR N
                INT     21H
                
                MOV     WORD PTR OLD_INTn,BX
                MOV     WORD PTR OLD_INTn+2,ES

                MOV     AH,25H
                MOV     AL,9cH
                MOV     DX,OFFSET NEW_INTn      ;DS=CS
                INT     21H

                MOV     DX,(H_LEN+15)/16+10H
                INT     21H
MAIN            ENDP
CODE            ENDS
                END     MAIN