exp84.asm

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;Index I/O port and data port

STACK   SEGMENT  STACK
        DW      100 DUP(?)
STACK   ENDS


DATA            SEGMENT PARA
INDEX_PORT      DW      3B4H
VIDEO_INIT      DB      38H,2DH,2EH,07H,5BH,02H,57H,57H
                DB      02H,03H,00H,00H,00H,00H,00H,00H
DATA            ENDS

CODE            SEGMENT PARA
                ASSUME  CS:CODE,DS:DATA,SS:STACK
MAIN            PROC    FAR

                MOV     AX,DATA
                MOV     DS,AX

                MOV     AX,0003H
                INT     10H     ;SET VIDEO MODE AS 3
                
                LEA     SI,VIDEO_INIT
                MOV     DX,INDEX_PORT

                CALL    IOPORT_INIT     ;RNTRY SI,DX

                MOV     AX,4C00H
                INT     21H
MAIN            ENDP

IOPORT_INIT     PROC    NEAR
                ;ENTRY SI=INIT DATA ADDR
                ;      DX=INDEX IO PORT ADDR

                PUSH    BX
                CLD
                MOV     CX,16
                MOV     BL,0
INIT_LP:        MOV     AL,BL
                OUT     DX,AL

                INC     DX
                LODSB
                OUT     DX,AL

                DEC     DX
                INC     BL
                LOOP    INIT_LP

                POP     BX
                RET
IOPORT_INIT     ENDP

CODE            ENDS
                END     MAIN