Editor RealTime Real time m1o2 fxp Eitan Ronn Braude lab02

;   Programmed By : m1o2
;   Course : Real-Time Systems
;   Date : 25.03.2012

; Cursor2.asm
;
;This program demonstrates cursor manipulation.
;
;
Stak              SEGMENT PARA STACK 'STACK'
DB                 256 DUP(0)
Stak              ENDS
;
Data               SEGMENT PARA PUBLIC 'Data'
                    Base dw 0
                    Direction db 0
;
Data               ENDS
Code               SEGMENT PARA PUBLIC 'Code'
                   .386  ; Enable 386 commands

SetCursorPos          PROC    NEAR
; Set Cursor to position in BX
; Input: BX
; Output: None

  MOV              DX,3D4H  ; Point to 3D4H - 3D5H port pair
  MOV              AL,14    ; Address of cursor register pos high byte
  MOV              AH,BH    ; Get desired value of cursor pos high byte
  OUT              DX,AX    ; Port(3D4h) = 14, Port(3D5h) = Value of BH
;
  MOV              AL,15    ; Address of cursor register pos low byte
  MOV              AH,BL    ; Get desired value pf cursor pos low byte
  OUT              DX,AX    ; Port(3D4h) = 15, Port(3D5h) = Value of BL
;
  RET                     ; Return to caller
SetCursorPos          ENDP
;

;
Start              PROC    FAR
;
;STANDARD PROGRAM PROLOGUE
;
  ASSUME           CS:Code
  PUSH             DS          ; Save PSP segment address
  MOV              AX,0
  PUSH             AX          ; Save INT 20h address offset (PSP+0)
  MOV              AX,Data
  MOV              DS,AX       ; Establish Data segment addressability
  ASSUME           DS:Data
;
;Part1 : Initialize the display adapter
;
  MOV              AH,0          ; Select function = 'Set mode'
  MOV              AL,2          ; 25x80 color image
  INT              10h           ; Adapter initialized. Page 0 displayed
;
  MOV              AX,0B800h     ; Segment address of memory on color adapter
;
  MOV              ES,AX         ; Set up extra segment register
;
; Write 'A' in mid screen
;
  mov BX,(12*80+40)
  mov si, 2*(12*80+40)
  ;mov bx, 1
  ;mov si, 0
  mov cl, 'A'
  mov ch, 0Eh
  mov Base, 0
;
; Set the cursor address registers
;

  CALL SetCursorPos
;
;PART 2 : Wait for key strike
;
; Wait for key
;
    jmp ShowAscii

NextLoop:
  MOV              AH,0       ; Wait and read key
  INT              16h        ;
  CMP              AH,1       ; Is it Esc?
  JE               ToReturn   ; Yes - Return to DOS
  ;
  ;
  cmp ah, 75
  je Left
  cmp ah, 72
  je Up
  cmp ah, 80
  je Down
  cmp ah, 77
  je Right
  cmp ah, 59
  je AddAttribute
  cmp ah, 60
  je MaxCursor
  cmp ah, 61
  je MinCursor
  ;<DEBUG>
  cmp ah, 62
  je MinAttribute
  cmp ah, 63
  je MaxAttribute
  ;</DEBUG>


    mov cl, al
 ShowAscii:
  mov word PTR ES:[si],cx
  inc bx
  add si, 2
  jmp SetNewCursor
 Left:
    dec bx
    sub si, 2
    jmp SetNewCursor
 Up:
    sub bx, 80
    sub si, 2*80
    jmp SetNewCursor
Down:
    add bx, 80
    add si, 2*80
    jmp SetNewCursor
 Right:
    inc bx
    add si, 2
    jmp SetNewCursor
AddAttribute:
    inc ch
    JMP NextLoop   ; Repeat main loop
MaxAttribute:
    mov ch, 255
    JMP NextLoop   ; Repeat main loop
MinAttribute:
    xor ch, ch
    JMP NextLoop   ; Repeat main loop
MaxCursor:
    mov dx, 3D4h
    mov ax, 10
    out dx, ax
    mov ax, 0f0bh
    out dx, ax
    JMP NextLoop   ; Repeat main loop
MinCursor:
    mov dx, 3D4h
    mov ax, 0e0ah
    out dx, ax
    mov ax, 0f0bh
    out dx, ax
    JMP NextLoop   ; Repeat main loop
    ;
    ;
SetNewCursor:

    cmp bx, Base
    jl below                    ; we might need to scroll up
    mov ax, bx
    sub ax, Base                ; find abs( line - base )
    cmp ax, 0
    jge AfterABS
    neg ax                      ; abs
AfterABS:
    cmp ax, 2000                ; abs( line - base ) > 2000 ?
    jbe update
    jmp above
below :
    cmp bx, 0
    jge continueScroll
below_Zero_No_Scroll:           ; we are at the first row, can't do up
    add bx, 80
    add si, 2*80
    jmp update
continueScroll:
    sub Base, 80
    jmp scroll
above:
    add Base, 80
Scroll:

    push bx
    mov bx, Base

    mov dx, 3D4h
    mov al, 12
    mov ah, bh
    out dx, ax

    mov al, 13
    mov ah, bl
    out dx, ax

    pop bx
update:
    call SetCursorPos

    JMP NextLoop   ; Repeat main loop
;
ToReturn:
                   MOV  AX,2
                   INT  10h
                   RET
Start              ENDP
Code               ENDS
  END              Start