Computer Select (Limited Edition)/Computer Select.iso/pcmag/v11n07/dosclip.asm

Assembly Source File | 1992-04-03 | 69KB | 1,973 lines

            page    66,132
;============================================================================
; DOSCLIP.COM impliments a DOS clipboard
;
;       Usage: DOSCLIP [/B][/U]
;
;              B = Use Video BIOS calls
;              U = Uninstall
;
; Revision History:
;
;       Version 1.0     Initial Release
;
;============================================================================
POPTIME         equ     9                       ;Allow 1/2 second to popup
COPYTIME        equ     180                     ;Allow 10 seconds to copy

STACKSIZE       equ     512                     ;TSR stack
INSTDATASIZE    equ    offset DataBlockEnd - offset DataBlock
MSGBOX_BUFFSIZE equ     1 * 132 * 2             ;Screen save buff for title
HELPBOX_BUFFSIZE equ    5 * 132 * 2             ;Screen save buff for help

RES_STACK       equ     offset end_of_resident + STACKSIZE
MSGBOX_BUFFER   equ     offset end_of_resident + STACKSIZE
ATTR_BUFFER     equ     MSGBOX_BUFFER + MSGBOX_BUFFSIZE

;----------------------------------------------------------------------------
; BIOS Data segment
;----------------------------------------------------------------------------
bios_data       segment at 40h
            org     17h
shift_state     db      ?                       ;State of keyboard shift keys
        org    1Ah
keybuff_head    dw    ?            ;Start ptr for keyboard buff
keybuff_tail    dw    ?             ;End ptr for keyboard buff

            org     4Eh
video_buffoff   dw      ?                       ;Offset of video buffer
            org     63h
video_ioregs    dw      ?                       ;I/O addr of video controller
        org    80h
keybuff_start    dw    ?            ;Start ptr for keyboard buff
keybuff_end    dw    ?             ;End ptr for keyboard buff
video_rows      db      ?                       ;Number of rows on the screen
bios_data       ends

;----------------------------------------------------------------------------
; DOSCLIP Code and Data segments
;----------------------------------------------------------------------------
            code    segment
            assume  cs:code

            org     2ch
env_segment     dw      ?                       ;Word containing the segment
                                            ;  of the program's env. block.
            org     80h
command_tail    db      ?                       ;Offset of the command tail.

            org     100h
prog:           jmp     initialize
;---------------------------------------------------------------------------            pushf
; Resident Data (Global to all sessions)
;---------------------------------------------------------------------------            pushf
program         db      13,10
program1    db    "DOSCLIP 1.0 "
copyright       db      "(c) 1992 Douglas Boling"
program2    db    10,13
            db      "First published in PC Magazine, April 14, 1992"
            db      13,10,"$",1Ah

def_marked_bw   db      70h                     ;Default marked attr B/W
def_text_bw     db      70h                     ;Default text attr B/W
bw_segment    dw    0B000h            ;Segment of B/W video memory

def_marked_clr  db      70h                     ;Default marked attr Color
def_text_clr    db      71h                     ;Default text attr Color
clr_segment    dw    0B800h            ;Segment of color video memory

attr_buffsize    dw    1024            ;Size of attribute buffer
helpbox_buff      dw    0               ;Pointer to helpbox buffer

copykey        db    2eh            ;Hotkey for copy command 'C'
copyshift    db    08h             ;Shift for copy hotkey. 'Alt'
pastekey    db    2Fh            ;Hotkey for paste command 'V'
pasteshift    db    08h             ;Shift for paste hotkey. 'Alt'

clipboard_buff    dd    0            ;Pointer to clipboard buffer
clipboard_size    dw    4096            ;Max size of clipboard
clipboard_dptr    dd    0            ;Ptr data in clipboard
clipboard_dsize    dw    0            ;Size of data in clipboard

win_enhanced    db    0            ;Enhanced mode Windows active

indos_ptr       dd      -1                      ;Pointer to INDOS flag
criterr_ptr     dd      -1                      ;Pointer to DOS crit err flag

int08h          dd      -1                      ;Int 08 vector (Timer)
int09h          dd      -1                      ;Int 09 vector (Keyboard HW)
int10h          dd      -1                      ;Int 10 vector (Video BIOS)
int13h          dd      -1                      ;Int 13 vector (Disk BIOS)
int16h          dd      -1                      ;Int 16 vector (Keyboard)
int28h          dd      -1                      ;Int 28 vector (DOS Idle)
int2Fh          dd      -1                      ;Int 2F vector (DOS Multiplex)

keycodes        db      3bh,51h,49h,4fh,47h,48h,50h,74h,73h,4bh,4dh
keycodes_end    =       $

keyjmp_table    dw      offset cursor_rt        ;Index into key routines are
        dw      offset cursor_lt        ;  inverse of order of
            dw      offset cursor_clt       ;  keycode array.
            dw      offset cursor_crt
            dw      offset cursor_dn
            dw      offset cursor_up
            dw      offset cursor_home    ;Home
            dw      offset cursor_end    ;End
            dw      offset cursor_top    ;Page Up
            dw      offset cursor_bottom    ;Page Down
            dw      offset showhelp        ;F1

helptag         db      "F1 for Help "
helptag_end    =    $
        db    0            ;Terminating 0 for helptag

no_help        db    0            ;Blocks help msg
;                        1234567891123456789212345678931234567894
helpmsg1        db      " <Cursor> keys delete box/move cursor   "
            db      " <Shift><Cursor> keys size box",0
helpmsg2        db      " <Home>   Move to start of line         "
            db      " <End>    Move to end of line",0
helpmsg3        db      " <Pg Up>  Move to top of screen         "
            db      " <Pg Dn>  Move to bot of screen",0
helpmsg4        db      " <C>      Copy box into clipboard       "
            db      " <V>      Paste clipboard data",0
helpmsg5        db      " <Esc>    Exit the program",0
;
;Screen variables
;
BIOSFlag    db    0            ;1 = Use Vid BIOS calls
video_ptr    label    dword
video_offset    dw    0            ;Offset of video memory
video_seg    dw    0            ;Segment of video memory
;
;Switcher global data structures
;
StartupInfo     =       $
 sisVersion     dw      3                       ;Switcher structure ID
 sisNextDev     dd      0                       ;Ptr to prev startup structure
 sisVirtDevFile dd      0                       ;Ptr to name of opt dev drvr
 sisReferenceData dd    0                       ;Data for Win dev drivr
 sisInstData    dd      0                       ;Ptr to instance mem list

DataBlockPtr    dd      0                       ;Ptr to instance data
DataBlockSize   dw      0                       ;Size of instance data
StackBlockPtr   dd      0                       ;Ptr to instance stack
StackBlockSize  dw      0                       ;Size of instance stack
            dd      0                       ;Ptr to next block = 0 to
            dw      0                       ;  terminate list
;============================================================================
;Instance data
;============================================================================
DataBlock    =    $
;
; Program Instance data
;
hotshift        db      0ah                     ;Shift condition for popup
popflag         db      0                       ;Go active counter

int08_active    db      0                       ;Interrupt active flag
int09_active    db      0                       ;Interrupt active flag
int10_active    db      0                       ;Interrupt active flag
int13_active    db      0                       ;Interrupt active flag
int28_active    db      0                       ;Interrupt active flag
int2F_active    db      0                       ;Interrupt active flag
main_active     db      0                       ;TSR active flag

saved_ss        dw      0            ;Saved forground stack ptr
saved_sp        dw      0

copy_flag    db    0            ;Flag indicating copy to clip
paste_flag    db    0            ;Flag indicating paste

marked_attr     db      0                       ;Screen attr for marked area
text_attr       db      0                       ;Attribute for msg box text

cursor_pos      dw      0                       ;Cursor position at popup
cursor_type     dw      0                       ;Cursor shape at popup

screen_page     db      0                       ;Active video page
screen_size     label   word
screen_cx       db      0                       ;Screen columns
screen_cy       db      0                       ;Screen rows

marked_pos1     label   word
marked_x1       db      0                       ;Marked area starting column
marked_y1       db      0                       ;marked area starting row
marked_pos2     label   word
marked_x2       db      0                       ;Marked area ending column
marked_y2       db      0                       ;marked area ending row

oldmarked_pos1  label   word
oldmarked_x1    db      0                       ;Marked area starting row
oldmarked_y1    db      0                       ;marked area starting column
oldmarked_pos2  label   word
oldmarked_x2    db      0                       ;Marked area columns
oldmarked_y2    db      0                       ;marked area rows

boxactive       db      0                       ;Flag for message box

DataBlockEnd    =    $

;============================================================================
; VIDEOINT processes BIOS video services interrupt (Int 10h)
;============================================================================
videoint        proc    far
            assume  cs:code,ds:nothing,es:nothing
            inc     cs:int10_active
            pushf
            call    cs:[int10h]             ;Call old int
            dec     cs:int10_active
            iret                            ;Return
videoint        endp

;============================================================================
; DISKINT processes BIOS disk services interrupt (Int 13h)
;============================================================================
diskint         proc    far
            assume  cs:code,ds:nothing,es:nothing
            inc     cs:int13_active
            pushf
            call    cs:[int13h]             ;Call old int
            pushf
            dec     cs:int13_active
            popf
            ret     2                       ;Return preserving flags
diskint         endp

;============================================================================
; TIMERINT processes timer interrupt (Int 08h)
;============================================================================
timerint        proc    far
            assume  cs:code,ds:nothing,es:nothing
            pushf
            call    cs:[int08h]             ;Call old int 8

        push    ax
        push    ds
        mov    ax,cs
        mov    ds,ax
        assume    ds:code

            cmp     int08_active,0          ;See if we are in this
            jne     timerint_exit1          ;  routine already
            inc     int08_active            ;Set int active flag

            cmp     popflag,0               ;See if we need to try to
            jne     timer_check             ;  pop up

            cmp     paste_flag,1            ;See if there is data to
        je      timer_paste_2           ;  paste from clipboard
        ja      timer_paste
timerint_exit:
            dec     int08_active            ;Clear int active flag
timerint_exit1:
        pop    ds
        pop    ax
            iret                            ;Return
timer_check:
            call    check_system            ;See if system OK to pop up
            or      ax,ax
            jne     timerint_dec
            call    main                    ;Call the TSR
            mov     popflag,1
timerint_dec:
            dec     popflag
        jmp     short timerint_exit
timer_paste_2:
            cmp     paste_flag,1            ;See if there is data to
        jne    timerint_exit        ;  paste
            call    push_key
        jnc    timer_paste_2
            jmp     short timerint_exit
timer_paste:
        cmp    win_enhanced,0        ;See if Win/386 active
        je    timer_paste_1

        call    getwinclip        ;Get data from the clipboard
        cmp    ax,-1            ;If -1, can't open clipboard,
        je    timerint_exit        ;  try again later.
        mov    paste_flag,0         ;If 0, no data available.
        or     ax,ax
        je    timerint_exit
        mov    clipboard_dsize,ax        ;Else, AX = bytes
        mov    ax,word ptr clipboard_buff    ;  read from CB.
        mov    word ptr clipboard_dptr,ax
        mov    paste_flag,1
        jmp    short timer_paste_2
timer_paste_1:
        mov    paste_flag,0        ;If no Win/386, see if any
        cmp    clipboard_dsize,0    ;  data in the clipboard.
        je    timerint_exit        ;  If not, cancel paste.
        mov    paste_flag,1
        jmp    short timer_paste_2
timerint        endp

;============================================================================
; KEYINT processes keyboard interrupts (Int 09h)
;============================================================================
keyint          proc    far
            assume  cs:code,ds:nothing,es:nothing
            push    ax
            push    ds
            mov     ax,40h
            mov     ds,ax                   ;Set ES to bios data segment
            assume  ds:bios_data
            mov     ah,ds:[shift_state]
            and     ah,0fh                  ;Mask lock bits
            cmp     ah,cs:[copyshift]
            je      keyint_copy
keyint_1:
            cmp     ah,cs:[pasteshift]
            je      keyint_paste
keyint_jmp:
            pop     ds
            pop     ax
            jmp    cs:[int09h]             ;Call old int 9
keyint_exit:
                cli                             ;Disable interrupts
                in      al,61h                  ;Reset the keyboard
                mov     ah,al                   ;  controller
                or      al,80h
                out     61h,al
                mov     al,ah
                out     61h,al

                mov     al,20h                  ;Signal end-of-interrupt to
                out     20h,al                  ;  the interrupt controller
                sti                             ;Enable interrupts
            pop     ds
            pop     ax
        iret
keyint_copy:
        in    al,60h            ;Get scan code from keyboard
        cmp    al,cs:copykey
        jne    keyint_1
        mov     cs:popflag,POPTIME      ;Set timer to pop up
            jmp     short keyint_exit
keyint_paste:
        in    al,60h            ;Get scan code from keyboard
        cmp    al,cs:pastekey        ;Compare to paste hotkey
        jne    keyint_jmp
        mov    cs:paste_flag,2        ;Set Paste flag
            jmp     short keyint_exit
keyint          endp

;============================================================================
; IDLEINT processes DOS Idle interrupt (Int 28h)
;============================================================================
idleint         proc    far
            assume  cs:code,ds:nothing,es:nothing
            pushf
            call    cs:[int28h]             ;Call old int

        push    ds
        push    cs
        pop    ds
        assume    ds:code
            cmp     int28_active,0          ;See if we are in this
            jne     idleint_exit1           ;  routine already
            inc     int28_active            ;Set int active flag
            cmp     popflag,0               ;See if we need to try to
            jne     idle_check              ;  pop up
idleint_exit:
            dec     int28_active            ;Clear int active flag
idleint_exit1:
        pop    ds
            iret                            ;Return
idle_check:
            push    ax
            call    check_system            ;See if OK to pop up.  Ignore
            or      al,al                   ;  INDOS since in idle.
            jne     idleint_1
            mov     popflag,0               ;Clear popup flag
            call    main                    ;Call the TSR
idleint_1:
            pop     ax
            jmp     short idleint_exit
idleint         endp

;============================================================================
; MUXINT processes DOS multiplex interrupt (Int 2Fh)
;============================================================================
muxint          proc    far
            assume  cs:code,ds:nothing,es:nothing

        cmp    ax,1605h        ;See if Windows launch
        je    mux_winstart
        cmp    ax,1606h        ;See if Windows terminate
        je    mux_winend
        cmp    ax,1608h        ;See if Windows launch
        je    mux_wingo         ;  complete

        cmp     ax,4b05h                ;See if switcher get instance
            je      init_instance           ;  data.
muxint_jmp:
            jmp     cs:[int2Fh]             ;Jump to old int
mux_winend:
            test    dx,01h                  ;See if enhanced mode Windows
            jne     muxint_jmp
        dec    cs:win_enhanced        ;Clear Enhanced mode win flag
            jmp     short muxint_jmp
mux_wingo:
        cmp    cs:clipboard_dsize,0    ;If Windows starts and we
        je    muxint_jmp        ;  have data in our
        cmp    cs:win_enhanced,0    ;  clipboard, copy our
        je    muxint_jmp        ;  data to the Win clipboard
        mov    cs:copy_flag,COPYTIME
        jmp    short muxint_jmp
mux_winstart:
            test    dx,01h                  ;See if enhanced mode Windows
            jne     init_instance
            inc     cs:win_enhanced
init_instance:
            pushf
            call    cs:[int2fh]             ;Call old int
            mov     word ptr cs:[sisNextDev],bx
            mov     word ptr cs:[sisNextDev+2],es
            push    cs                      ;ES:BX point to switcher struc
            pop     es
            mov     bx,offset StartupInfo
            jmp     short muxint_exit
muxint_exit:
            iret
muxint        endp

;---------------------------------------------------------------------------            pushf
; Check System Determines if the system is in a state compatible with TSRs
; Exit: AL - ORed flags for DOS Idle OK
;       AH - State of INDOS flag
;---------------------------------------------------------------------------            pushf
check_system    proc    near
            assume  cs:code,ds:code,es:nothing
            push    bx
            push    ds
            xor     ax,ax
            or      al,int10_active         ;Check BIOS video int
            or      al,int13_active         ;Check BIOS disk int
            lds     bx,criterr_ptr          ;Check DOS critical error
            or      al,byte ptr ds:[bx]     ;  flag.
            lds     bx,cs:indos_ptr         ;Check INDOS flag
            mov     ah,byte ptr ds:[bx]
check_sys_exit:
            pop     ds
            pop     bx
            ret
check_system    endp

;-----------------------------------------------------------------------------
; GETWINCLIP  Gets any data from the Windows Clipboard
; Exit AX - FF Can't open clipboard
;           0  Error in clipboard or clipboard data not available
;           Else, number of bytes read from clipboard
;-----------------------------------------------------------------------------
getwinclip    proc    near
        assume    ds:code
        mov    ax,1701h        ;Open Clipboard
        int    2fh
        or    ax,ax            ;Error opening, exit
        mov    ax,-1
        je    getwinclip_exit1
        push    bx
        push    dx
        push    es
        mov    ax,1704h        ;Get clipboard data size
        mov    dx,7            ;Request OEM Text
        int    2fh
        or    dx,dx            ;See if too much data
        jne    getwinclip_exit
        cmp    ax,clipboard_size
        jbe    getwinclip_1
        xor    ax,ax            ;Indicate error
        jmp    short getwinclip_exit
getwinclip_1:
        cmp    dx,ax                 ;If 0 size, no data in
        je    getwinclip_exit        ;  correct format.
        push    ax
        mov    ax,1705h        ;Get clipboard data
        les    bx,clipboard_buff
        mov    dx,7            ;Get OEM text
        int    2fh
        or    ax,ax
        pop    ax
        je    getwinclip_exit
        dec    ax
getwinclip_exit:
        push    ax
        mov    ax,1708h        ;Close Clipboard
        int    2fh
        pop    ax
        pop    es
        pop    dx
        pop    bx
getwinclip_exit1:
        ret
getwinclip    endp

;-----------------------------------------------------------------------------
; GETCLIPSIZE  Gets the size of the data in the Windows clipboard
;-----------------------------------------------------------------------------
getclipsize    proc    near
        assume    ds:code
        mov    ax,1701h        ;Open Clipboard
        int    2fh
        or    ax,ax            ;Error opening, exit
        je    getclipsize_exit
        mov    ax,1704h        ;Get clipboard data size
        mov    dx,7            ;Request OEM Text
        int    2fh
        mov    ax,1708h        ;Close Clipboard
        int    2fh
        pop    es
        pop    dx
        pop    bx
getclipsize_exit:
        ret
getclipsize    endp

;-----------------------------------------------------------------------------
; SETWINCLIP  Sets the Windows clipboard
; Exit:  ZF - Set if error
;-----------------------------------------------------------------------------
setwinclip    proc    near
        assume    ds:code
        push    bx
        push    cx
        push    dx
        push    si
        push    es
        mov    ax,1700h        ;Check API
        int    2fh
        or    ax,ax            ;no API
        je    setwinclip_exit1
        mov    ax,1701h        ;Open Clipboard
        int    2fh
        or    ax,ax            ;Error opening, exit
        je    setwinclip_exit1
        mov    ax,1702h        ;Clear Clipboard
        int    2fh
        or    ax,ax            ;Error, exit
        je    setwinclip_exit1
        mov    ax,1703h        ;Set clipboard data
        les    bx,clipboard_buff    ;ES:BX ptr to data
        xor    si,si            ;SI,CX = data size
        mov    cx,clipboard_dsize
        mov    dx,7            ;Data format is OEM text
        int    2fh
setwinclip_exit:
        mov    ax,1708h        ;Close Clipboard
        int    2fh
        or    ax,ax            ;Set ZF if error
setwinclip_exit1:
        pop    es
        pop    si
        pop    dx
        pop    cx
        pop    bx
        ret
setwinclip    endp

;-----------------------------------------------------------------------------
; INCKEYPTR Incriments the keyboard buffer pointer
; Entry: DI - Current Keyboard tail pointer
;-----------------------------------------------------------------------------
inckeyptr    proc    near
        assume    ds:bios_data
        inc    di            ;Make room in buffer
        inc    di
        cmp    di,ds:[keybuff_end]    ;Get ptr to end of buffer
        jne    inckeyptr_1
        mov    di,ds:[keybuff_start]    ;Get ptr to buffer offset
inckeyptr_1:
        ret
inckeyptr    endp

;-----------------------------------------------------------------------------
; PUSH KEY  Fills the keyboard buffer with data from the clipboard.
; Exit: CF - Set if keyboard buffer full
;       AX - modified
;-----------------------------------------------------------------------------
push_key    proc    near
        assume    ds:nothing,es:nothing
        push    di
        push    si
        push    ds
        push    es
        cli
        mov    ax,bios_data
        mov    ds,ax
        assume    ds:bios_data
        cli                ;No interrupts
        mov    di,ds:[keybuff_tail]
        push    di
        call     inckeyptr
        cmp    di,ds:[keybuff_head]    ;See if buffer full
        pop    di
        stc
        je    push_key_exit

        les    si,cs:[clipboard_dptr]    ;Get ptr to clip data
        mov    ax,word ptr cs:[clipboard_buff]
        add    ax,cs:[clipboard_dsize] ;Add size of data
        cmp    ax,si            ;See if at end of buffer
        mov    al,es:[si]        ;Get clipboard byte
        jne    push_key_2        ;No, continue
        mov    cs:[paste_flag],0        ;Clear paste flag
        mov    si,word ptr cs:[clipboard_buff]    ;Reset data ptr
        dec    si
push_key_2:
        or    al,al            ;Don't stuff null char
        je    push_key_3
        cmp    al,0ah            ;Don't stuff line feeds
        je    push_key_3
          xor    ah,ah            ;Clear scan code
        cmp    al,0dh            ;If CR character, add proper
        jne    push_key_21        ;  scan code for Word Perfect
        mov    ah,1ch
push_key_21:
        mov    ds:[di],ax        ;Push data into keyboard buff
        call    inckeyptr
        mov    ds:[keybuff_tail],di    ;Save keybuff ptr
push_key_3:
        inc    si            ;Update clip data ptr
        mov    word ptr cs:[clipboard_dptr],si    ;Save clipdata ptr
        clc
push_key_exit:
        sti                ;Allow interrupts
        pop    es
        pop    ds
        pop    si
        pop    di
        ret
push_key    endp

;============================================================================
; MAIN  This routine does most of the work for the TSR
;============================================================================
main            proc    near
            assume  cs:code,ds:code,es:nothing
            cmp     main_active,0           ;See if already active
            jne     main_exit
            cli
            inc     main_active
            mov     [saved_sp],sp           ;Save old stack pointer
            mov     [saved_ss],ss

            mov     ax,cs                   ;Set ss:sp to internal stack
            mov     ss,ax
            mov     sp,RES_STACK
            sti                ;Enable interrupts
            cld                ;Set string direction UP

            push    bx
            push    cx
            push    dx
            push    di
            push    si
            push    bp
            push    es

            mov     ah,0fh                  ;Get display mode
            int     10h
            cmp     al,7
            je      main_1                  ;Pop up only if in text mode.
            cmp     al,4
            jb      main_1
main_exit1:
            pop     es
            pop     bp
            pop     si
            pop     di
            pop     dx
            pop     cx
            pop     bx

            cli
            mov     ss,[saved_ss]           ;Restore old stack
            mov     sp,[saved_sp]
            dec     main_active
main_exit:
            ret
main_1:
        xor    dl,dl
        mov    no_help,dl        ;Enable help message
        mov    copy_flag,dl        ;Clear copy to clip flag
            cmp     ah,80
            jb      main_exit1
            mov     screen_page,bh          ;Save active video page
            mov     screen_cx,ah            ;Save screen columns

            mov     ah,3                    ;Get cursor position
            int     10h
            mov     cursor_pos,dx           ;Save cursor information
            mov     cursor_type,cx
        cmp    dh,0            ;If on top line, move down 1
        jne    main_11            ;  to miss banner.
        inc    dh
main_11:
        mov    marked_pos1,dx        ;Save initial cursor position
            mov     ax,40h
            mov     es,ax                   ;Set ES to bios data segment
            assume  es:bios_data
            mov     ah,12h                  ;Determine if CGA by checking
            mov     bl,10h                  ;  for EGA compatibility
            int     10h
            mov     al,24                   ;CGA, only 25 rows on screen
            cmp     bl,10h
            je      main_2

            mov     al,es:video_rows        ;Get number of rows on screen
main_2:
            mov     screen_cy,al        ;Save screen rows
        mov    ax,es:video_buffoff    ;Copy ptr to video memory
        mov    video_offset,ax

            mov     ax,marked_pos1        ;Copy starting pos to ending
            mov     marked_pos2,ax        ;  pos to zero block.
            mov     oldmarked_pos1,ax
            mov     oldmarked_pos2,ax

            test    es:video_ioregs,40h     ;See if color or monochrome
            jne     main_colorvid

        mov    si,offset def_marked_bw    ;Point to B/W parameters
            jmp     short main_3
main_colorvid:
        mov    si,offset def_marked_clr ;Point to color parameters
main_3:
            push    ds
            pop     es
            assume  es:code

        mov    di,offset marked_attr    ;Copy default attributes
        movsw
        lodsw                ;Get Video buffer segment
        mov    video_seg,ax

            mov     ah,1            ;Hide the cursor by changing
            mov     cx,200h                 ;  the size of the cursor
            int     10h

        call    init_attrlist        ;Initialize attr save list
        jc    main_end1

            mov     dx,marked_pos1          ;Mark initial cursor where
            call    getchar                 ;  the old cursor was
            mov     ah,marked_attr        ;Mark cursor position on
            call    putchar            ;  screen.
main_loop:
            cmp     boxactive,1             ;If box active, don't reprint
            je      main_4                  ;  the box.

        mov    al,marked_y2        ;If cursor on top line, don't
        or    al,marked_y2        ;  print the title box.
        je    main_4
            call    msgbox                  ;Draw title box
main_4:
        call    getkey            ;Wait for a key
            cmp     al,27                   ;If ESC, end.
            je      main_end
            cmp     ah,pastekey             ;If 'v' paste and exit
            je      main_paste
            cmp     ah,28                   ;If Enter, copy and exit
            je      main_copy
            cmp     ah,copykey              ;If 'c' copy and exit
            je      main_copy
            mov     al,ah            ;Copy scan code
main_6:
            mov     di,offset keycodes
            mov     cx,offset keycodes_end - offset keycodes
            repne   scasb
            jne     main_loop
            shl     cx,1            ;Convert key num into jump
            mov     bx,cx            ;  table index.
        mov    ax,marked_pos2        ;Preload parameters into regs
        mov    cx,screen_size        ;  to save code
            call    [keyjmp_table+bx]    ;Call key routine
            jmp     short main_loop
main_copy:
        mov    copy_flag,1
        jmp    short main_end
main_paste:
        cmp    win_enhanced,0        ;If enhanced mode Windows
        je    main_paste_1        ;  active, get clipboard
        call    getwinclip        ;  data from the Windows
        jmp    short main_end        ;  Clipboard.
main_paste_1:
        cmp    clipboard_dsize,0    ;If clipboard empty, don't
        je    main_end        ;  paste.
        mov    paste_flag,1
main_end:
            call    clearmarked             ;Restore attributes
            call    clearbox                ;Delete title box
main_end1:
            mov     ah,1                    ;Set cursor type
            mov     cx,cursor_type
            mov     bh,screen_page
            int     10h
            mov     ah,2                    ;Set cursor position
            mov     dx,cursor_pos
            int     10h
            jmp     main_exit1
main            endp

;-----------------------------------------------------------------------------
; CURSOR KEYS Handles the actions of the cursor keys as the user uses them
;             to mark the selected area.
; Entry: AL - marked_x2
;        AH - marked_y2
;        CL - screen_cx
;        CH - screen_cy
;-----------------------------------------------------------------------------
cursor_keys     proc    near
; CURSOR HOME  Moves the cursor to the left most column
cursor_home:
            xor     al,al            ;Zero current column
            jmp     short cursor_1
; CURSOR END  Moves the cursor to the right most column
cursor_end:
            mov     al,cl            ;Set Cur column to screen cols
            dec     al
            jmp     short cursor_1
; CURSOR TOP  Moves the cursor to the top row
cursor_top:
            mov     ah,1                    ;Move to line 1 to avoid
            jmp     short cursor_1          ;  title erase
; CURSOR END  Moves the cursor to the bottom row
cursor_bottom:
            mov     ah,ch            ;Set Cur Row to screen rows
            jmp     short cursor_1
; CURSOR UP  Moves the marked orgin up one row
cursor_up:
            or      ah,ah
            je      cursor_1
            dec     ah
            jmp     short cursor_1
; CURSOR DN  Moves the marked orgin down one row
cursor_dn:
            cmp     ah,ch
            je      cursor_1
            inc     ah
            jmp     short cursor_1
; CURSOR CLT  Moves the marked orgin left 8 columns
cursor_clt:
        sub    al,8
        jae    cursor_1
            xor     al,al
            jmp     short cursor_1
; CURSOR CRT  Moves the marked orgin right 8 columns
cursor_crt:
        add    al,8
        dec    cl
        cmp    al,cl
        jb    cursor_1
            mov     al,cl
            jmp     short cursor_1
; CURSOR LT  Moves the marked orgin left one col
cursor_lt:
            or      al,al
            je      cursor_1
            dec     al
            jmp     short cursor_1
; CURSOR RT  Moves the marked orgin right one col
cursor_rt:
        dec    cl
            cmp     al,cl
            jae     cursor_1
            inc     al
cursor_1:
        mov    marked_pos2,ax        ;Save new position
        push    ax
            mov     ah,2                    ;Get shift state
            int     16h
            and     al,3
        pop    ax
            jne     cursor_2
            mov     marked_pos1,ax          ;Not shifted, set points equal
cursor_2:
            or      ah,ah                   ;If cursor on top line, clear
            jne     cursor_3                ;  title box so user can see
            call    clearbox                ;  what is on top line.
cursor_3:
            call    drawmarked
            ret
cursor_keys     endp

;-----------------------------------------------------------------------------
; DRAWMARKED  Displays the marked area by changing the screen attributes
;             inside the marked area.
;-----------------------------------------------------------------------------
drawmarked      proc    near
            push    es

            mov     ax,marked_pos1
            mov     dx,marked_pos2
            cmp     dx,oldmarked_pos2
            jne     drawmarked_1

            cmp     ax,oldmarked_pos1
            je      drawmarked_exit
drawmarked_1:
            mov     bx,offset marked_pos1
            mov     cx,4
drawmarked_2:
            call    find_min                ;AX = upper left corner
            call    find_max                ;DX = lower right corner
            add     bx,2
            loop    drawmarked_2
drawmarked_7:
            sub     dx,ax                   ;Compute size of area

            xor     cx,cx
            mov     cl,dl                   ;Copy column count
            mov     si,cx
            inc     si
            mov     cl,dh                   ;Copy row count
            inc     cx
            mov     dx,ax                   ;Copy starting row, column
drawmarked_8:
            push    cx                      ;Save row count
            push    dx                      ;Save cursor position
            mov     cx,si                   ;Get column count
drawmarked_9:
            mov     bx,offset marked_pos1
            call    chk_inwin
            mov     ah,al                   ;Save in marked area flag

            mov     bx,offset oldmarked_pos1
            call    chk_inwin

            cmp     ah,al                   ;See if in or out of both
            je      drawmarked_11           ;  areas. If so, no change.

            push    ax                      ;Save in-window flags
            call    getchar
            pop     bx
            or      bh,bh                   ;See if in marked area
            je      drawmarked_10

            mov     ah,marked_attr        ;Mark character
            call    putchar

            jmp     short drawmarked_11
drawmarked_10:
        call    get_attr        ;Get saved screen attribute
            call    putchar            ;Restore attribute
drawmarked_11:
            inc     dl
            loop    drawmarked_9

            pop     dx
            pop     cx
            inc     dh
            loop    drawmarked_8

            mov     ax,marked_pos1          ;Update old pointers
            mov     oldmarked_pos1,ax
            mov     ax,marked_pos2
            mov     oldmarked_pos2,ax
drawmarked_exit:
            pop     es
            ret
drawmarked      endp

;-----------------------------------------------------------------------------
; CLEARMARKED  Restores the marked area to its original screen attributes
;-----------------------------------------------------------------------------
clearmarked     proc    near
            assume  ds:code
        push    es
            mov     bx,offset marked_pos1
            call    compute_box
            sub     ax,dx
            xor     cx,cx
            mov     cl,al
            mov     si,cx                   ;Save column count
            inc     si
            mov     cl,ah
            inc     cx
        xor    bx,bx
        cmp    copy_flag,0
        je    clearmarked_3
        mov    bx,clipboard_size
        les    di,clipboard_buff
        mov    word ptr [clipboard_dptr],di
clearmarked_3:
            push    cx
            push    dx
            mov     cx,si            ;Get row count
clearmarked_4:
            call    getchar
        or    bx,bx            ;If copying data to
        je    clearmarked_5        ;  clipboard, save char.
        stosb
        dec    bx
clearmarked_5:
        call    get_attr        ;Get saved screen attribute
            call    putchar
            inc     dl
            loop    clearmarked_4
        or    bx,bx
        je    clearmarked_6
        mov    ax,0a0dh        ;Append CR-LF to line
        stosw
        dec    bx
        dec    bx
clearmarked_6:
            pop     dx
            pop     cx
            inc     dh
            loop    clearmarked_3
        cmp    copy_flag,0
        je    clearmarked_exit
        xor    al,al
        stosb
        dec    bx
        sub    bx,clipboard_size
        not    bx
        mov    clipboard_dsize,bx
        mov    ax,word ptr cs:[clipboard_buff]
        mov    word ptr cs:[clipboard_dptr],ax
        cmp    win_enhanced,0        ;If enhanced mode Windows
        je    clearmarked_exit    ;  active, save data to
        call    setwinclip        ;  Windows clipboard
clearmarked_exit:
        pop    es
            ret
clearmarked     endp

;-----------------------------------------------------------------------------
; GET ATTR  Gets a saved attribute in the attribute buffer for a given
;           cursor location.
; Entry:  DX - Row, Column of character
; Exit:   AH - Attribute
;-----------------------------------------------------------------------------
get_attr    proc    near
        push    cx
        push    dx
        push    si
        push    ax
        call    compute_offset        ;Get count into buffer
        mov    si,ATTR_BUFFER
        xor    ax,ax
        mov    dx,ax
get_attr_1:
        lodsb                ;Get count byte
        inc    si
        or    al,al
        je    get_attr_exit
        sub    cx,ax
        jae    get_attr_1
        mov    dh,[si-1]        ;Get attribute
get_attr_exit:
        pop    ax
        mov    ah,dh            ;Copy attribute
        pop    si
        pop    dx
        pop    cx
        ret
get_attr    endp

;-----------------------------------------------------------------------------
; INIT ATTRLIST  Initializes the attribute list
;-----------------------------------------------------------------------------
init_attrlist    proc    near
            assume  ds:code
        mov    bx,screen_size        ;Get size of screen
        inc    bh
        inc    bh
        xor    ax,ax
        mov    dx,ax            ;Start at top left corner
        mov    cx,ax
        xchg    bh,cl            ;CX-Col count, BX-Row cnt
        mov    si,bx
        mov    di,ATTR_BUFFER        ;Get pointer to buffer
        call    getchar
        mov    bh,ah
        mov    bl,0
init_attrlist_1:
        push    cx
        push    dx
        mov    cx,si            ;Get number of columns
init_attrlist_2:
        call    getchar         ;Read attribute
        cmp    bh,ah            ;Compare attributes
        jne    init_attrlist_newblk    ;If different write block
        inc    bl            ;Incriment count
        cmp    bl,-1            ;If count full, write block
        je    init_attrlist_newblk
        mov    bh,ah            ;Copy attribute value
init_attrlist_3:
        inc    dl            ;Next column
        loop    init_attrlist_2
        pop    dx
        pop    cx
        inc    dh            ;Next row
        loop    init_attrlist_1
        clc
init_attrlist_exit:
            ret
init_attrlist_newblk:
        mov    ds:[di],bx        ;Write old block to list
        inc    di            ;Update ptr
        inc    di
        mov    bl,1            ;New count
        mov    bh,ah            ;Copy new attribute
        cmp    di,helpbox_buff
        jb    init_attrlist_3        ;If list runs into the help
        inc    no_help            ;  buffer, disable help
        push    ax
        mov    ax,helpbox_buff        ;If past helpbox buffer, exit
        add    ax,HELPBOX_BUFFSIZE
        cmp    di,ax
        pop    ax
        jb    init_attrlist_3        ;If list past help box
        stc                        ;  buffer, exit prog.
        jmp    short init_attrlist_exit
init_attrlist    endp

;-----------------------------------------------------------------------------
; COMPUTE OFFSET  Computes the offset into the attribute buffer for a
;                 given cursor location.
; Entry:  DX - Row, Column of character
; Exit:   CX - Offset in buffer.
;-----------------------------------------------------------------------------
compute_offset  proc    near
            push    ax
        push    dx
            mov     al,dh                   ;Copy column
            mul     screen_cx               ;Mul by width of screen
            xor     dh,dh
            add     ax,dx                   ;Add row
        xchg    cx,ax
        pop    dx
            pop     ax
            ret
compute_offset  endp

;-----------------------------------------------------------------------------
; CHK INWIN  Determines if a character is inside the bounds of an area
; Entry:  BX - Pointer to bounding rectangle
;           x1  db  point 1 column
;           y1  db  point 1 row
;           x2  db  point 2 column
;           y2  db  point 2 row
;         DX - Row, Column of character
; Exit:   AL - <> 0 if inside area
;-----------------------------------------------------------------------------
chk_inwin       proc    near
            push    bx
            push    cx

            push    ax                      ;Save AX
            push    dx                      ;Save current cursor pos
            call    compute_box             ;DX = UL corner, AX = LR corner
            pop     bx
            xchg    bx,dx                   ;DX = cur cursor, BX=UL corner
            mov     cx,ax                   ;CX = LR corner
            pop     ax                      ;Restore AX

            mov     al,0                    ;Clear inbox flag

            cmp     dl,bl                   ;See if above starting row
            jb      chk_inwin_exit
            cmp     dh,bh                   ;See if left of starting col
            jb      chk_inwin_exit

            cmp     dl,cl                   ;See if below ending row
            ja      chk_inwin_exit
            cmp     dh,ch                   ;See if right of ending col
            ja      chk_inwin_exit
            inc     al
chk_inwin_exit:
            pop     cx
            pop     bx
            ret
chk_inwin       endp

;-----------------------------------------------------------------------------
; FIND MIN  Computes the smaller of two screen coordinates.
; Entry:  AX - Row, Column of 1st coordinate
;         BX - Pointer to 2nd coordinate
; Exit:   AX - Result coordinate.
;-----------------------------------------------------------------------------
find_min        proc    near
            cmp     al,[bx]
            jbe     find_min_1
            mov     al,[bx]
find_min_1:
            cmp     ah,[bx+1]
            jbe     find_min_2
            mov     ah,[bx+1]
find_min_2:
            ret
find_min        endp

;-----------------------------------------------------------------------------
; FIND MAX  Computes the larger of two screen coordinates.
; Entry:  DX - Row, Column of 1st coordinate
;         BX - Pointer to 2nd coordinate
; Exit:   AX - Result coordinate.
;-----------------------------------------------------------------------------
find_max        proc    near
            cmp     dl,[bx]
            jae     find_max_1
            mov     dl,[bx]
find_max_1:
            cmp     dh,[bx+1]
            jae     find_max_2
            mov     dh,[bx+1]
find_max_2:
            ret
find_max        endp

;-----------------------------------------------------------------------------
; COMPUTE BOX  Puts the starting row/column in DX and the SI and CX
; Entry:  BX - Pointer to coordinates
; Exit:   AX - Ending row/column
;         DX - Starting row/column
;-----------------------------------------------------------------------------
compute_box     proc    near
            mov     ax,[bx]
            mov     dx,[bx+2]

            cmp     al,dl
            ja      compute_box_1
            xchg    al,dl
compute_box_1:
            cmp     ah,dh
            ja      compute_box_2
            xchg    ah,dh
compute_box_2:
            ret
compute_box     endp

;-----------------------------------------------------------------------------
; SHOWHELP  Displays a help screen on the first three lines of the display
;-----------------------------------------------------------------------------
showhelp        proc    near
        cmp    byte ptr no_help,0    ;See if help msg disabled.
        jne    showhelp_exit
            mov     dh,1                    ;Box at top of screen
            mov     cx,5
            mov     di,helpbox_buff
showhelp_1:
            push    cx
            call    saveline
            inc     dh
            pop     cx
            loop    showhelp_1

            mov     dh,1
            mov     si,offset helpmsg1      ;Write help text line
            call    writeline
            inc     dh                      ;Move to next line
            mov     si,offset helpmsg2
            call    writeline
            inc     dh                      ;Move to next line
            mov     si,offset helpmsg3
            call    writeline
            inc     dh                      ;Move to next line
            mov     si,offset helpmsg4
            call    writeline
            inc     dh                      ;Move to next line
            mov     si,offset helpmsg5
            call    writeline

        call    getkey            ;Wait for a key
            mov     dh,1                    ;Box at top of screen
            mov     cx,5
            mov     si,helpbox_buff
showhelp_2:
            push    cx
            call    restoreline
            inc     dh
            pop     cx
            loop    showhelp_2
showhelp_exit:
            ret
showhelp        endp

;-----------------------------------------------------------------------------
; MSGBOX  displays a message in a text window on the top line of the
;         screen.  The current data on the screen is saved.
;-----------------------------------------------------------------------------
msgbox          proc    near
            mov     dh,0                    ;Box at top of screen
        mov    al,boxactive
            cmp     al,2                 ;Display sum only
            je      msgbox_1
            or      al,al                  ;If box already displayed,
            jne     msgbox_1                ;  don't save screen data.
            mov     di,MSGBOX_BUFFER
            call    saveline
msgbox_1:
        mov    si,offset program1
        mov    cx,offset program2 - offset program1
        xor    dx,dx
msgbox_11:
        lodsb
        call    writechar
        loop    msgbox_11
        xor    cx,cx
        mov    cl,screen_cx
        sub    cl,offset helptag_end - offset helptag
        ja    msgbox_2
        mov    cl,screen_cx
        inc    ch
msgbox_2:
        push    dx
msgbox_3:
            mov     al,' '                  ;Pad line with spaces
            call    writechar
            cmp     dl,cl
            jb      msgbox_3
        or    ch,ch
        jne    msgbox_5
msgbox_4:
        mov    si,offset helptag
        call    writestr
msgbox_5:
        pop    dx
            mov     boxactive,1             ;Set box active flag
            ret
msgbox          endp

;-----------------------------------------------------------------------------
; CLEARBOX  removes the title box from the screen.
;-----------------------------------------------------------------------------
clearbox        proc    near
            cmp     boxactive,0             ;If box already displayed,
            je      clearbox_2              ;  don't save screen data.
            mov     si,MSGBOX_BUFFER
            mov     dh,0                    ;Box at top of screen
            call    restoreline
            mov     boxactive,0             ;Clear box displayed flag
clearbox_2:
            ret
clearbox        endp

;-----------------------------------------------------------------------------
; WRITELINE  Writes a line of help text to the screen.  The line is padded
;            with spaces to the right.
; Entry: DH - Line on screen to write
;        SI - Pointer to ASCIIZ text
;-----------------------------------------------------------------------------
writeline       proc    near
            push    dx
            xor     dl,dl                   ;Start at left side of screen
            call    writestr                ;Write string
writeline_2:
            mov     al,' '                  ;Pad line with spaces
            call    writechar
            cmp     dl,screen_cx
            jb      writeline_2
            pop     dx
            ret
writeline       endp

;-----------------------------------------------------------------------------
; SAVELINE  Saves the contents of a screen line ot a buffer
; Entry: DH - Line on screen to save
;        DI - Pointer to save buffer
;-----------------------------------------------------------------------------
saveline        proc    near
            push    dx
            xor     dl,dl                   ;Start at left side of screen
            xor     cx,cx
            mov     cl,screen_cx
saveline_1:
            call    getchar                 ;Read character from screen
            stosw
            inc     dl                      ;Point to next character
            loop    saveline_1
            pop     dx
            ret
saveline        endp

;-----------------------------------------------------------------------------
; RESTORELINE  Restores the screen that was covered by a line of program
;              helptext.
; Entry: DH - Line on screen to restore
;        SI - Pointer to buffer that contains original screen contents
;-----------------------------------------------------------------------------
restoreline     proc    near
            push    dx
            xor     dl,dl                   ;Start at left side of screen
            xor     cx,cx
            mov     cl,screen_cx
restoreline_1:
            lodsw
            call    writechar1              ;Read character from screen
            loop    restoreline_1
            pop     dx
            ret
restoreline     endp

;-----------------------------------------------------------------------------
; WRITESTR  Writes a string to the screen.
; Entry: DH,DL - Row/Column to write the string
;        SI - Pointer to ASCIIZ text
;-----------------------------------------------------------------------------
writestr        proc    near
            mov     ah,text_attr
writestr1:
            lodsb                           ;Read text from string, then
            or      al,al                   ;  call putchar to write to
            je      writestr_1        ;  the screen.
            call    writechar1
            jmp     short writestr1
writestr_1:
            ret
writestr        endp

;-----------------------------------------------------------------------------
; WRITECHAR  Writes a character to the screen
; Entry: AL - Character
;        DX - Row, Column
;-----------------------------------------------------------------------------
writechar       proc    near
            mov     ah,text_attr
writechar1:
            call    putchar
            inc     dl
            ret
writechar       endp

;-----------------------------------------------------------------------------
; GETCHAR  Reads a character and its attribute from the screen
; Entry:  DH - Row of character to read
;         DL - Column of character to read
; Exit:   AL - Character
;         AH - Attribute
;-----------------------------------------------------------------------------
getchar         proc    near
            push    bx
        cmp    BIOSFlag,0
        jne    getchar_bios
        push    cx
        push    si
        push    ds
        call    compute_offset        ;Get offset into buffer
        shl    cx,1            ;Double for char and attr
        lds    si,video_ptr        ;Get ptr to video memory
        add    si,cx            ;Double since char and attr
        lodsw                ;Read char/attribute
        pop    ds
        pop    si
        pop    cx
        jmp    short getchar_exit
getchar_bios:
            mov     ah,2                    ;Set cursor
            mov     bh,screen_page
            int     10h
            mov     ah,8                    ;Read character/attr
            int     10h
getchar_exit:
            pop     bx
            ret
getchar         endp

;-----------------------------------------------------------------------------
; PUTCHAR  Writes a character and its attribute to the screen
; Entry:  AL - Character to write
;         AH - Attribute to write
;         DH - Row of character to write
;         DL - Column of character to write
;-----------------------------------------------------------------------------
putchar         proc    near
            push    bx
            push    cx
            push    ax
        cmp    BIOSFlag,0
        jne    putchar_bios
        push    di
        push    es
        call    compute_offset        ;Get offset into buffer
        shl    cx,1             ;Double since char and attr
        les    di,video_ptr
        add    di,cx                  ;Add to start of buffer
        stosw                ;Read char/attribute
        pop    es
        pop    di
        jmp    short putchar_exit
putchar_bios:
            mov     ah,2                    ;Set cursor
            mov     bh,screen_page
            int     10h
            pop     ax
        push    ax
            mov     bl,ah                   ;Copy attribute
            mov     ah,9                    ;Read character/attr
            mov     cx,1
            int     10h
putchar_exit:
        pop    ax
            pop     cx
            pop     bx
            ret
putchar         endp

;-----------------------------------------------------------------------------
; GETKEY  Waits for a key from the keyboard.
; Exit:   AX - Scan code, ASCII char from keyboard.
;-----------------------------------------------------------------------------
getkey          proc    near
            mov     ah,1                    ;Check for key
            int     16h
            jnz     getkey_exit
            int     28h                     ;Call DOS Idle
        mov    ax,1680h        ;Release Timeslice
        int    2fh
            jmp     short getkey
getkey_exit:
            xor     ax,ax                   ;Get key
            int     16h
        ret
getkey          endp
        align    16
end_of_resident =       $

;----------------------------------------------------------------------------
; Non-resident data.
;----------------------------------------------------------------------------
alrdy_installed db      0                       ;Installed flag
installed_seg   dw      0                       ;Segment of installed code
dos_version     dw      0                       ;DOS version

infomsg2        db      "DOSCLIP uninstalled$"

errmsg0         db      "Need DOS 3.0 or greater$"
errmsg1         db      "DOSCLIP not installed$"
errmsg2         db      "Usage: DOSCLIP [/B][/U]",13,10
            db      "/B = Use Video BIOS",13,10
            db      "/U = Uninstall",13,10,"$"
errmsg3         db      "Can",39,"t uninstall$"
errmsg4         db      "DOSCLIP already installed$"
errmsg5         db      "Can not find Critical error flag$"
endmsg          db      13,10,"$"

infomsg1        db      "DOSCLIP installed",13,10,10
            db      "Copy key is "
        db    "Alt  C",13,10
            db      "Paste key is "
        db    "Alt  V","$"

;----------------------------------------------------------------------------
; Initialization routine.
;----------------------------------------------------------------------------
initialize      proc    near
            assume  cs:code,ds:code,es:code
            cld
            mov     dx,offset program       ;Print copyright message
            call    printmsgcr

            mov     ah,30h                  ;Get DOS version
            int     21h
            xchg    al,ah                   ;Swap major, minor numbers
            mov     dx,offset errmsg0       ;Bad DOS version
            cmp     ah,3                    ;Run if DOS 3.0 or greater.
            jb      disp_error
            mov     dos_version,ax          ;Save version number

            mov     ax,offset end_of_code+512       ;Set stack ptr
            mov     sp,ax
            add     ax,15
            mov     cl,4                    ;Convert offset to segment size
            shr     ax,cl
            mov     ah,4ah                  ;Reduce memory allocation
            int     21h

            call    find_installed        ;See if already installed
            jc      init_1
            inc     alrdy_installed        ;Yes, set flag
            mov     installed_seg,es        ;Save seg of installed code
init_1:
            push    ds
            pop     es
            mov     dx,offset errmsg4       ;Default message
            mov     di,80h            ;Parse command line
            xor     cx,cx
            or      cl,[di]                 ;Get length of cmd line
            je      init_exit
init_2:
            mov     al,'/'
            repne   scasb                   ;Find command line switches
            jne     init_exit
            mov     al,[di]                 ;Get comamnd line switch
            or      al,20h
            cmp     al,'b'                  ;See if Video BIOS parameter
            jne     init_3
            inc    BIOSFlag
            jmp     short init_2
init_3:
            cmp     al,'u'                  ;See if uninstall
            je    init_4
            mov     dx,offset errmsg2       ;Print useage statement
;
;Display error message.
;
            assume  ds:nothing
disp_error:
            push    cs
            pop     ds
            assume  ds:code
            call    printmsgcr              ;print string

            mov     ax,4c01h                ;Terminate with RC = 1
            int     21h
init_4:
            call    remove                  ;Remove installed copy
            jc    disp_error
        jmp    short exit
init_exit:
            cmp     alrdy_installed,0
            jne     disp_error
            call    install
            jc      disp_error
exit:
            mov     ax,4C00h                ;Terminate with RC = 0
            int     21h
initialize      endp

;-----------------------------------------------------------------------------
; INSTALL Installs the program
;-----------------------------------------------------------------------------
            assume  cs:code,ds:code,es:code
install         proc    near
            mov     ah,34h                  ;Get ptr to INDOS flag
            int     21h
            mov     word ptr indos_ptr,bx
            mov     word ptr indos_ptr[2],es
            call    findCEF                 ;Get ptr to crit error flag
            jnc     install_1
            jmp     install_error
install_1:
;
;Set interrupt vectors
;
            mov     word ptr criterr_ptr,bx
            mov     word ptr criterr_ptr[2],es
            mov     al,08h                  ;Get/set the timer interrupt
            mov     dx,offset timerint
            mov     di,offset int08h
            call    set_interrupt
            mov     al,09h                  ;Get/set the keyboard int
            mov     dx,offset keyint
            mov     di,offset int09h
            call    set_interrupt
            mov     al,10h                  ;Get/set the video interrupt
            mov     dx,offset videoint
            mov     di,offset int10h
            call    set_interrupt
            mov     al,13h                  ;Get/set the disk interrupt
            mov     dx,offset diskint
            mov     di,offset int13h
            call    set_interrupt
            mov     al,28h                  ;Get/set the DOS idle int
            mov     dx,offset idleint
            mov     di,offset int28h
            call    set_interrupt
            mov     al,2Fh                  ;Get/set the DOS Multiplex
            mov     dx,offset muxint
            mov     di,offset int2Fh
            call    set_interrupt

        push    cs
        push    cs
        pop    ds
        assume    ds:code
        pop    es
        assume    es:code
            mov     dx,offset infomsg1      ;Print program installed msg
            call    printmsgcr
;
;Init buffer pointers.
;
        mov    dx,ATTR_BUFFER        ;Set pointers for resident
        add    dx,attr_buffsize    ;  code.
        mov    helpbox_buff,dx
        add    dx,HELPBOX_BUFFSIZE
;
;Init clipboard pointers.
;
        mov    word ptr [clipboard_buff],dx
        mov    bx,dx            ;Save size of save data area
        add    dx,clipboard_size    ;Add size of clipboard
        mov    ax,cs
         mov    word ptr [clipboard_buff+2],ax
         mov    word ptr [clipboard_dptr+2],ax
         mov    word ptr [clipboard_dsize],0
         mov    paste_flag,0
;
;Init switcher structures
;
            mov     word ptr [DataBlockPtr+2],ax
            mov     word ptr [DataBlockPtr],offset DataBlock
            mov     word ptr [DataBlockSize],INSTDATASIZE

            mov     word ptr [StackBlockPtr+2],ax
            mov     word ptr [StackBlockPtr],offset end_of_resident
        sub    bx,offset end_of_resident    ;Compute size of
            mov     word ptr [StackBlockSize],bx    ;  Data save area

            mov     word ptr [sisInstData+2],ax
            mov     ax,offset DataBlockPtr
            mov     word ptr [sisInstData],ax
        push    dx            ;Save Ptr to end of resident

            mov     ax,1600h                ;See if Enhanced mode windows
            int     2fh
            or      al,al
            je      nowin
            inc     win_enhanced            ;Set enhanced mode flag
nowin:
        pop     dx            ;Get Ptr to end of resident
            add     dx,15
            mov     cl,4
            shr     dx,cl
            mov     ax,3100h                ;Terminate and stay resident
            int     21h
install_error:
            ret
install         endp

;-----------------------------------------------------------------------------
; REMOVE uninstalls the installed program from memory.
;-----------------------------------------------------------------------------
remove          proc    near
            assume  ds:code,es:code
            push    ds
            push    es

            mov     ds,installed_seg        ;Point DS to installed code
            assume  ds:nothing

            mov     dx,offset errmsg1       ;Not installed message
            cmp     alrdy_installed,0
            je      remove_error1

            mov     al,8                    ;Restore int 8 (Timer)
            mov     dx,offset timerint
            mov     di,offset int08h
            call    restore_int
            jc      remove_error
            mov     al,9                    ;Restore int 9 (keyboard)
            mov     dx,offset keyint
            mov     di,offset int09h
            call    restore_int
            jc      remove_error
            mov     al,10h                  ;Restore int 10h (BIOS Video)
            mov     dx,offset videoint
            mov     di,offset int10h
            call    restore_int
            jc      remove_error
            mov     al,13h                  ;Restore int 13h (BIOS disk)
            mov     dx,offset diskint
            mov     di,offset int13h
            call    restore_int
            jc      remove_error
            mov     al,28h                  ;Restore int 28h (DOS Idle)
            mov     dx,offset idleint
            mov     di,offset int28h
            call    restore_int
            jc      remove_error
            mov     al,2Fh                  ;Restore int 2Fh (DOS Mux)
            mov     dx,offset muxint
            mov     di,offset int2Fh
            call    restore_int
            jc      remove_error
            mov     es,ds:[2ch]             ;Get installed env seg
            mov     ah,49h
            int     21h                     ;Free installed env segment
            push    ds
            pop     es
            mov     ah,49h                  ;Free installed program segment
            int     21h
            mov     ax,cs
            mov     ds,ax
            mov     es,ax
            mov     dx,offset infomsg2      ;Print program removed msg
            call    printmsgcr
            clc
remove_exit:
            pop     ds
            pop     es
            ret
remove_error:
            mov     dx,offset errmsg3       ;Can't uninstall msg
remove_error1:
            stc
            jmp     short remove_exit
remove          endp

;-----------------------------------------------------------------------------
; SETINTERRUPT Get and sets an interrupt
; Entry: AL - Interrupt number
;        DX - Pointer to new interrupt routine
;        DI - Pointer to storage location for old interrupt vector
;-----------------------------------------------------------------------------
            assume  cs:code,ds:code,es:nothing
set_interrupt   proc    near
            push    es
            push    ax
            mov     ah,35h                  ;DOS get interrupt
            int     21h
            pop     ax
            mov     word ptr [di],bx        ;Save old vector
            mov     word ptr [di+2],es
            mov     ah,25h                  ;DOS set interrupt
            int     21h
            pop     es
            ret
set_interrupt   endp

;-----------------------------------------------------------------------------
; RESTOREINT Checks to see if an interrupt vector has been changed, if not
;            the interrupt vector is restored with its original value
; Entry:    AL - Interrupt number
;        DS:DX - Pointer to current interrupt routine
;        DS:DI - Pointer to old interrupt vector
;-----------------------------------------------------------------------------
            assume  cs:code,ds:nothing
restore_int     proc    near
            push    es
            push    ax
            mov     ah,35h                  ;DOS get interrupt
            int     21h
            pop     ax                      ;Get back interrupt number
            cmp     dx,bx                   ;Compare routine offset
            jne     restoreint_error
            mov     bx,es                   ;Get current vector segment
            mov     cx,ds                   ;Get installed segment
            cmp     cx,bx                   ;Compare routine segment
            jne     restoreint_error
            push    ds
            lds     dx,ds:[di]              ;Get old vector
            mov     ah,25h                  ;DOS set interrupt
            int     21h
            clc
            pop     ds
restoreint_exit:
            pop     es
            ret
restoreint_error:
            stc
            jmp     short restoreint_exit
restore_int     endp

;-----------------------------------------------------------------------------
; FINDCEF  Finds the DOS ErrorMode (Critical error) flag
; Exit:   ES:BX - Segment,offset of ErrorMode flag
;         CF - Clear if flag found
;-----------------------------------------------------------------------------
findCEF         proc    near
        mov    ah,34h            ;Get InDOS address
        int    21h
        dec    bx
        cmp    dos_version,30ah    ;If DOS 3.1 or later, ErrorMode
        jnc    findCEF_exit        ;  sits before InDOS.

            mov     ax,3e80h                ;CMP opcode
        mov     si,028cdh               ;Int 28 Opcode
        mov     dl,75h                  ;JNE Opcode
            mov     cx,-1                   ;max search length
            mov     di,bx                   ;start at INDOS address
findCEF_1:
        repne   scasb                   ;do the search
            jcxz    findCEF_notfound        ;branch if search failed
        cmp     es:[di],ah              ;Check other half of CMP opcode
        jne     findCEF_1
        cmp     byte ptr es:[di+4],dl   ;Check for JNE
        jne     findCEF_1
        cmp     word ptr es:[di+6],si   ; Check for Int 28h call
        jne     findCEF_1               ;Resume loop if not found
        inc     di
        mov     bx,es:[di]              ;Get offset of ErrorMode flag
        clc
findCEF_exit:
        ret
findCEF_notfound:
        stc
        mov    dx,offset errmsg5    ;Can't find Critical Error flg
        jmp     short findCEF_exit
findCEF        endp

;-----------------------------------------------------------------------------
; FIND INSTALLED Find the installed code by scanning the memory control blocks.
; Exit:   AX - Segment of installed code if found.
;         CF - Clear if installed code found
;-----------------------------------------------------------------------------
find_installed  proc    near
            assume  ds:code,es:code
            mov     word ptr prog,0
            mov     bx,0A000h               ;Start at upper mem blk start
            mov     ax,cs                   ;keep CS value in AX
find_installed_1:
            inc     bx                      ;increment search segment value
            mov     es,bx
            assume  es:nothing
            cmp     ax,bx                   ;not installed if current
            je      find_installed_2        ;  segment is found.
            call    cmpheader
            jne     find_installed_1        ;loop back if not found

            clc
find_installed_exit:
            ret
find_installed_2:
            stc
            jmp     short find_installed_exit
find_installed  endp

;-----------------------------------------------------------------------------
; CMPHEADER compares the first 16 bytes of this file with the segment
;           pointed to by ES.
; Entry:  DS - code segment
;         ES - pointer to segment to compare
; Exit:   ZF - 0 = segments match.
;-----------------------------------------------------------------------------
cmpheader       proc    near
            assume  ds:code,es:nothing
            mov     si,offset prog          ;Search this segment for ASCII
            mov     di,si                   ;  fingerprint.
            mov     cx,16
            repe    cmpsb
            ret
cmpheader       endp

;-----------------------------------------------------------------------------
; PRINTMSG prints the message pointed to by DX to the screen.
; Entry:  DX - pointer to ASCII message terminated by $
;-----------------------------------------------------------------------------
printmsg        proc    near
            assume  ds:nothing,es:nothing
            push    ds
            push    cs
            pop     ds
            assume  ds:code
            mov     ah,9                    ;Print message
            int     21h
            pop     ds
            ret
printmsg        endp

;-----------------------------------------------------------------------------
; PRINTMSGCR calls PRINTMSG, then appends a carriage return to the message.
; Entry:  DX - pointer to ASCII message terminated by $
;-----------------------------------------------------------------------------
printmsgcr      proc    near
            assume  ds:nothing,es:nothing
            push    dx
            call    printmsg
            mov     dx,offset endmsg
            call    printmsg
            pop     dx
            ret
printmsgcr      endp
            even
end_of_code     =       $
code            ends

end             prog