Gold Medal Software 2/Gold Medal Software Volume 2 (Gold Medal) (1994).iso/prog/asm_n_z.arj/NEWINIT.ASM

Assembly Source File | 1987-05-05 | 18KB | 574 lines

title newinit.asm
comment |--------------------------------------------------------------
In text modes the active page can be switched between 1-4 (80-col) or
 1-8 (40-col) by pressing ALT and the corresponding # on the TOP ROW. This
 feature can only be used to view the other pages.  Results of all CON I/O
 while paging are unpredictable and messy.
As protection against duplicate installation, INT 15h with AX = X'FF00'
 returns AX = X'ABCD'.
The keypad "5" key will toggle processing.  While paused,  a flashing,
 highlighted "P" will appear in the lower-right corner (not graphics).
If Numlock is on, shift-"5" is required.  If Alt or Ctrl are pressed, nothing
 changes.  Scroll Lock, Caps Lock, and Ins are irrelevant.
This program sets the video mode to 80 col monochrome.
The enhanced keyboard can be toggled on/off with Alt-PrtSc, and a 1/8 sec
 2000 Hz tone will sound when toggled on.  (The PrtSc modification cannot
 be turned off.)
NOTE: If both  shift keys are depressed at installation time, the
 installation will be cancelled, with errorlevel set to X'AB'.
------------------------------------------------------------------------|
bios_data    segment at 0040h
    org    17h
kb_flag    db    ?    ; keyboard status byte
kb_flag_1    db    ?

    org    49h
v_mode    db    ?    ; BIOS video mode
v_width    db    ?    ; BIOS screen width

    org    62h
v_page    db    ?    ; BIOS video page
mystery_w    dw    ?    ; word used by pause routine
mystery_b    db    ?    ; byte used by pause routine
bios_data ends

cseg    segment
    assume    cs:cseg
    org    80h
parm_cnt    db    ?    ; parameter count
parm_data    db    ?    ; start of parameter data space
    org    100h    ; .COM file

begin:    jmp    init_vectors    ; initialize and attach to DOS

; addresses of video and keyboard I/O ROM routines
prtsc    dd    0    ; INT 5
kybd    dd    0    ; INT 9
cass    dd    0    ; INT 15h
kybd_io    dd    0    ; INT 16h

; constants and segments
bios_dat    dw    40h    ; bios_data segment
mono_seg    dw    0b000h    ; segment of MGA
color_seg    dw    0b800h    ; segment of CGA
datatbl    db    2,3,0,1,6,4,5    ; scan-code to video mode data
indicator equ "P"+256*10001111b    ; an highlighted, flashing "P"
row equ 24            ; position of indicator for mono moniter
col equ 79
mono_point    equ 2*((row*80)+col)    ; offset in mono segment

; variable data
vdata    db    0    ; current video mode or page
code_seg    dw    0    ; CS of resident routines
graph_bit    db    0    ; flag to signal graphics mode
toggle    db    1    ; enables/disables enhanced keyboard

prtsc_int:    sti        ; enable interrupts
    push    ax    ; save regs
    push    dx
    mov    ah,2    ; read printer status
    xor    dx,dx    ; zero DX - LPT1
    int    17h    ; printer I/O
    xor    ah,30h    ; check for OFFLINE
    jnz    chk_shft    ; skip beep, prepare for exit
    pop    dx
no_dump:    pop    ax
    iret
chk_shft:    pop    dx
    push    ds
    mov    ds,bios_dat    ; set DS = X'40'
    assume    ds:bios_data
    test    kb_flag,00000010b    ; check for LEFT shift key
    pop    ds    ; restore regs
    jz    no_dump    ; skip screen dump if no LEFT shift
    pop    ax
    jmp    prtsc    ; print screen routine

calculate:    assume    ds:bios_data
    xor    ax,ax    ; zero AX
    xor    cx,cx    ; likewise
    mov    al,v_width    ; AX = 00 width
    mov    cl,v_page    ; save for later multiply
    mov    bx,25    ; calculate offset into page
    mul    bl
    dec    ax    ; = (25*width)-1
    shl    ax,1    ; MUL AX,2 - skip attribute bytes
    mov    bx,ax    ; save in BX
    mov    ax,2048    ; byte length of 40 column page
    cmp    v_width,40    ; check for 40 column screen
    je    multiply    ; if yes, leave AX alone
    shl    ax,1    ; if no, change to 80 column offset
multiply:    mul    cx    ; multiply by page number
    add    bx,ax    ; sum buffer offset with page offset
    mov    es,color_seg    ; load ES with CGA segment
    assume    es:nothing
skip_cga:    mov    cx,es:[bx]    ; save screen data in CX
    mov word ptr es:[bx],indicator   ; store flashing "P" on screen

rejoin:    ; branch made if graphics mode - skip indicator

    mov    dx,mystery_w    ; load mystery word
    add    dx,4    ; more mysterious code
    mov    al,mystery_b    ; load mystery byte
    out    dx,al    ; I have no clue what this does

    call    reset
    or    kb_flag_1,00001000b    ; turn ctrl-num-lock on
    sti        ; enable interrupts
again:    test    kb_flag_1,00001000b    ; check if ctrl-num-lock on
    jnz    again    ; if on, check again

    cli        ; disable interrupts (play it safe)
    test    graph_bit,1    ; check if graphics mode
    mov    graph_bit,0    ; reset graphics flag
    jnz    skip_mov    ; skip restoration of screen data
    mov    es:[bx],cx    ; restore screen data
skip_mov:    pop    es    ; restore regs
    pop    dx
    pop    cx
    pop    bx
    pop    ds
    pop    ax
    iret

pause:    assume    ds:bios_data    ; DS set in FIVE: routine
    push    bx    ; save BX (for active page)
    push    cx    ; save CX to use as scratch register
    push    dx
    push    es
    cmp    v_mode,4    ; check for text mode
    jb    calculate    ; continue if yes
    cmp    v_mode,7    ; check for monochrome buffer
    jne    no_p    ; skip "P" if graphics
    mov    es,cs:mono_seg    ; point ES to segment at 0b000h
    mov    bx,mono_point    ; offset into monochrome segment
    jmp short skip_cga    ; skip color setup

no_p:    mov    graph_bit,1    ; set graphics mode flag
    jmp short rejoin    ; rejoin main code

yes:    and    kb_flag_1,11110111b    ; turn ctrl-num-lock off
    call    reset    ; reset keyboard
    pop    ds
    pop    ax
    iret

    assume    ds:nothing
five:    push    ds    ; save data segment
    mov    ds,cs:bios_dat    ; point to keyboard data
    assume    ds:bios_data
    test    kb_flag_1,00001000b    ; check if Ctrl-NumLock on
    jnz    yes    ; if yes, unpause
    mov    al,kb_flag    ; get shift key status byte
    test    al,00001100b    ; check for Alt or Ctrl pressed
    jnz    quit    ; exit if so
    and    al,00100011b    ; isolate NumLock and Shift bits
    jz    pause    ; if zero (none pressed) then go!
    cmp    al,00100000b
    ja    pause    ; both NumLock & Shift must be pressed
            ; if not, then end
    assume    ds:nothing
quit:    pop    ds    ; restore regs
    pop    ax
    jmp    kybd    ; goto BIOS

    assume    ds:nothing
; intercepts INT 9
kybd_int:    push    ax    ; save reg
    in    al,60h    ; get scan code
    cmp    al,37h    ; scan code of PrtSc key
    je    tog_chk    ; check for Alt pressed before toggling
    test    toggle,1    ; check if enhanced keyboard enabled
    jz    off    ; if not, skip enhanced processing
    cmp    al,4ch    ; scan code of keypad "5" ?
    je    five    ; if yes, check further
    cmp    al,46h    ; check for Scroll-Lock (Break) key
    je    break    ; if so, look for Ctrl-Shift
off:    pop    ax    ;  if not, restore reg and
    jmp    kybd    ; goto BIOS

; check for right-shift-Ctrl
break:    push    ds    ; save reg
    mov    ds,bios_dat    ; set DS to bios data segment
    assume    ds:bios_data
    test    kb_flag_1,00001000b    ; check if ctrl-num-lock on
    jnz    quit    ; goto BIOS if yes
    test    kb_flag,00000001b    ; right shift key pressed?
    jz    quit
    test    kb_flag,00000100b    ; check for Ctrl key pressed
    jz    quit
    call    reset
    mov    ax,4ccah    ; DOS EXIT function 4C
            ;  ErrorLevel = 202
    int    21h
    pop    ds    ; restore regs
    pop    ax
    iret        ; return from key interrupt

tog_chk:    push    ds    ; save DS
    mov    ds,bios_dat    ; point DS to bios data segment
    assume    ds:bios_data
    test    kb_flag_1,00001000b    ; check for Ctrl-NumLock pause on
    jnz    quit    ; goto BIOS if yes
    test    kb_flag,00000111b    ; check for Ctrl or L/R shift pressed
    jnz    quit    ; don't toggle if yes - send key to bios
    test    kb_flag,00001000b    ; check for Alt pressed
    jz    quit    ; don't toggle if no - send key to bios
    xor    toggle,1    ; toggle
    jz    skip_beep    ; skip beep if toggled off
    push    cx    ; save count reg for delay
; beep
; Step 1 -- prepare the timer to receive its divisor
    mov     al,0b6h    ; timer mode register signal
    out     67,al    ; output to timer control port
; Step 2 -- send the divisor count to the timer
;   Divisor = (1,190,000 / desired frequency)
    mov     ax,595    ; divisor for 2000 Hz
    out     66,al    ; output low-order byte of divisor
    mov     al,ah    ;  high-order byte to output reg
    out     66,al    ; output high-order byte of divisor
; Step 3 -- turn on the two bits which activate the speaker, and the
;           timer's control of the speaker
    in      al,97    ; get current bit settings - port 97
    mov     ah,al    ; save port 97 to turn sound off
    or      al,03    ; turn on last two bits
    out     97,al    ;  send back the new value

    mov     cx,8000h    ; approx 1/8 second
delay:    loop    delay    ; sounding tone while counting
    mov     al,ah    ; restore original port 97
    out     97,al    ; stop tone
    pop     cx    ; restore count reg

skip_beep:    call    reset    ; reset kybd and interrupt controller
    pop    ds    ; restore regs
    assume    ds:nothing
    pop    ax
    iret

reset    proc
    in    al,61h    ; reset keyboard
    mov    ah,al
    or    al,80h
    out    61h,al
    mov    al,ah
    out    61h,al
    mov    al,20h    ; send end-of-interrupt signal
    out    20h,al    ;  to interrupt controller
    ret
reset endp

    assume    ds:nothing
cass_int:    cmp    ax,0ff00h    ; duplicate installation protection
    je    duped    ; yes
    jmp    cass    ; no, goto BIOS
duped:    mov    ax,0abcdh
    iret

nope:    jmp    kybd_io    ; goto BIOS

    assume    ds:nothing
kybd_io_int:
    test    toggle,1    ; check if enhanced keyboard enabled
    jz    nope    ; if not, goto bios
    test    ah,ah    ; check for AH = 0 (read key)
    jnz    nope    ; if not, goto bios
    pushf        ; simulate INT 16h
    call    kybd_io
    test    al,al    ; check for zero char code
    jz    extend    ; continue if extended character
    iret        ; return if not

extend:    cmp    ah,53h    ; skip predefined ext. functions
    ja    ext    ; extended function routine(s)
back:    iret        ; return if predefined

; branch made if code greater than predefined (3-53h)
ext:    cmp    ah,94    ; check for F21 (CTRL-F1)
    jb    back    ; end if below
    cmp    ah,103    ; CTRL-F10 - 67h
    ja    next    ; goto next function

    push    dx    ; save DX
    push    ax    ; save scan code

    mov    ah,2    ; read printer status
    xor    dx,dx    ; zero DX - LPT1
    int    17h    ; printer I/O
    xor    ah,30h    ; check for OFFLINE
    jz    offline    ; skip beep, prepare for exit

    pop    ax    ; retrieve scan code
    push    bx
    push    cx
    sub    ah,94    ; bring scan code down to 0-9
; mult AH by 3
    mov    bl,ah    ; save ah
    shl    ah,1    ; mult by 2
    add    bl,ah    ;  mult by 3
    xor    bh,bh    ; zero BH
    add    bx,offset PRNT_BUF    ; add mem loc to offset
    mov    cx,3    ; 3-char printer output
    xor    dx,dx    ; printer zero

loop1:    mov    al,3    ; full offset
    sub    al,cl    ; sub count from full offset
    xlat    cs:prnt_buf    ; get data in AL
    cmp    al,0ffh    ; check for end-of-string
    je    beep    ;  beep if EOS
    xor    ah,ah    ; zero AH - print char
    int    17h    ; BIOS printer I/O
    loop    loop1    ; next char

beep:    cmp    cl,3    ; check for null string
    je    p_end    ; skip beep if null
    mov    ax,0007    ; printer output / BEL
    int    17h    ; BIOS printer I/O
    mov    ax,000dh    ; printer output / CR
    int    17h    ; BIOS printer I/O

p_end:    pop    cx
    pop    bx
    sub    sp,2    ; fool next POP
offline:    pop    ax
    pop    dx
    xor    ax,ax    ; zero AX (read_char)
back3:    jmp    kybd_io_int    ; goto BIOS for next key

next:    cmp    ah,113    ; code > Alt-F10 ?
    ja    next1    ; yes - goto
    je    cls    ; if code = Alt-F10 - execute CLS
    cmp    ah,110    ; Alt-F7 < code < Alt-F10 ?
    ja    back3    ; null processing

    push    bx    ; save base reg for XLAT
    mov    al,ah    ; copy key code into AL for XLAT
    sub    al,104    ; bring key-code to 0-6
    mov    bx,offset datatbl    ; look-up table of video modes
    xlat    cs:datatbl
    xor    ah,ah    ; zero AH for INT 10h
    int    10h
    pop    bx    ; restore BX
            ; AH already zero - read_key
    jmp    kybd_io_int    ; goto bios

cls:    push    bx
    push    cx
    push    dx
    push    ds
    mov    ds,bios_dat
    assume    ds:bios_data
    mov    bh,7    ; attribute to use on blank window
    xor    cx,cx    ; upper left corner = 0,0
    mov    dh,24    ; bottom row to clear
    mov    dl,v_width    ; bios video width byte
    dec    dx    ; bios byte is either 40/80
    mov    ax,600h    ; AH=6 (scroll up) AL=0 (blank window)
    int    10h
    mov    bh,v_page    ; get current video page
    xor    dx,dx    ; upper left corner
    mov    ah,2    ; position cursor
    int    10h

    assume    ds:nothing
    pop    ds    ; restore regs
    pop    dx
    pop    cx
    pop    bx
    xor    ax,ax    ; read_key
    jmp    kybd_io_int    ; get next key

; code greater than 110, ALT-F7
next1:    cmp    ah,78h    ; ALT-1 (top row)
    jb    end_ext    ; end routine
    cmp    ah,127    ;     check code > ALT-8
    ja    end_ext
    push    bx    ; save regs
    push    ax
    mov    ah,15    ; read video state
    int    10h
    mov    vdata,al    ; save current mode
    cmp    al,3    ; check for graphics modes
    ja    back1    ; end if graphics
    pop    ax    ; retrieve char code
    mov    al,ah    ; char code into page result reg
    sub    al,78h    ; bring char code down to page code
    cmp    al,4    ; check for valid code 80 or 40
    jb    skip1    ; change if valid unconditionally
    cmp    vdata,1    ; check for 40 col display
    ja    back2    ; end if 80 col
skip1:    mov    ah,5    ; select active display page
    int    10h
    jmp short back2    ; finished

end_ext:            ; if key code not defined here,
    iret        ;  give other routines a chance

back1:    add    sp,2    ; skip AX on stack
back2:    pop    bx    ; restore BX
    xor    ax,ax    ; zero AH - read key
    jmp    kybd_io_int    ; get another char

; control codes for Gemini (Epson compatible)
prnt_buf    db    27,"V",1    ; slashed-zero      F1
    db    27,"@",0ffh    ; power-on reset        F2
    db    27,"B",1    ; 10 cpi (80 col)   F3
    db    15,0ffh,00    ; 17 cpi (132 col)      F4
    db    27,"E",0ffh    ; emphasized on     F5
    db    27,"F",0ffh    ; emphasized off        F6
    db    27,"S",0    ; superscript mode  F7
    db    27,"S",1    ; subscript mode        F8
    db    27,"U",1    ; unidirectional    F9
    db    27,"U",0    ; bidirectional         F10

end_of_resident:

print_help:
    xor    cx,cx    ; upper left row/column
    mov    dx,184fh    ; lower right row/column
    mov    bh,7    ; attribute for blank region
    mov    ax,600h    ; scroll up/blank entire window
    int    10h
    mov    ah,15    ; get video data
    int    10h    ; active page in BH
    xor    dx,dx    ; upper left row/column
    mov    ah,2    ; set cursor position
    int    10h
    mov    dx,offset help_text    ; get address of help screen
    mov    ah,9    ; DOS print string
    int    21h
    mov    ax,0ff00h    ; check (again) for duplicate installation
    int    15h
    cmp    ax,0abcdh
    je    skip_prnt    ; if yes, skip printing install instructions
    mov    dx,offset not_yet    ; message - type newinit install
    mov    ah,9    ; DOS print string
    int    21h
skip_prnt:    int    20h    ; terminate

init_vectors:
    mov    ds,bios_dat
    assume    ds:bios_data
    mov    al,kb_flag    ; get keyboard status byte
    xor    al,00000011b    ; check if both shift keys pressed
    jnz    continue    ; if not, continue with installation
    mov    ax,4cabh    ; DOS EXIT function, ERRORLEVEL = X'AB'
    int    21h

continue:    mov    ax,cs    ; set data segment to code segment
    mov    ds,ax
    assume    ds:cseg
    mov    code_seg,ax    ; save code segment for resident routine
    xor    cx,cx    ; zero CX
    mov    cl,parm_cnt    ; get number of parameters
    jcxz    print_help    ; print help screen
    mov    si,offset parm_data    ; start of parameter line
    cld        ; clear DF to increment SI
loop2:    lods    parm_data    ; get byte from parm_data
    cmp    al,"Z"+1    ; check if lower case
    jb    lp2
    sub    al,"a"-"A"    ; convert to lower case
    mov    [si-1],al    ; put back into param line
lp2:    loop    loop2    ; get next char

check:    mov    di,offset parm_data
    mov    al,"I"    ; search for "I"
    mov    cl,parm_cnt    ; number of characters to search
    repne scasb    ; scan parameter line
    jne    print_help    ; print help screen if not found
    mov    si,1 + offset key    ; "INSTALL" but past the "I"
    assume    es:cseg
    repne cmps parm_data,key    ; check for key in parameter line
    jne    print_help    ; if not found, print help screen
    mov    ax,0ff00h    ; if found, check for prev install
    int    15h    ; cassette (snicker!) interrupt
    cmp    ax,0abcdh    ; duplicate installation code
    jne    install    ; full speed ahead
    mov    dx,offset already    ; error message
    mov    ah,9    ; DOS print string
    int    21h
    int    20h    ; bye-bye

install:    mov    ax,2    ; AH=0 - set video mode
            ; AL=2 - 80 col mono
    int    10h
    mov    ax,3505h    ; get int vector for INT 5
    int    21h
    mov    word ptr prtsc,bx    ; save routine offset
    mov    word ptr prtsc[2],es    ; save routine segment
    mov    dx,offset prtsc_int    ; offset of new routine
            ; DS = CS above
    mov    ah,25h    ; set int vector for INT 5
    int    21h

    mov    ax,3509h    ; get int vector for INT 9
    int    21h
    mov    word ptr kybd,bx    ; save offset
    mov    word ptr kybd[2],es    ; save segment
    mov    dx,offset kybd_int    ; offset of user routine
    mov    ah,25h    ; set int vector
    int    21h

    mov    ax,3515h    ; get int vector for INT 15h
    int    21h
    mov    word ptr cass,bx    ; save offset
    mov    word ptr cass[2],es    ; save segment
    mov    dx,offset cass_int    ; offset of user routine
    mov    ah,25h    ; set int vector
    int    21h

    mov    ax,3516h    ; get int vector for INT 16h
    int    21h
    mov    word ptr kybd_io,bx    ; save offset
    mov    word ptr kybd_io[2],es    ; save segment
    mov dx, offset kybd_io_int    ; offset of user routine
    mov    ah,25h    ; set int vector
    int    21h

    mov    dx,offset installed    ; completed message
    mov    ah,9    ; DOS print string
    int    21h
    mov    dx,offset end_of_resident
    int    27h    ; terminate, remain resident

key    db    "INSTALL"    ; installation text key

already    db    13,10,10,9,9
    db    "This utility already resident.",13,7,10,10,"$"

installed    db    9,9,"NEWINIT is up and running.",10,10,"$"

help_text:    db    "This resident program modifies certain key combinations:",13,10
 db "1) PrtSc will only work if the left shift key is used.",13,10
 db "2) Ctrl-Right-Shift-Break forces a DOS function call X'4C' (EXIT) which will"
    db    13,10
 db "   exit the current program.  This avoids much of the need for Ctrl-Alt-Del."
    db    13,10
 db "   If exit is forced in this manner, errorlevel is set to X'CA' (202).",13,10
 db "3) Alt-1 thru Alt-8 (top row) will VIEW that display page (I/O not reliable)."
    db    13,10
 db "4) Alt-F1 thru Alt-F7 change the video mode.",13,10
 db "      F1 = 80 col mono (at startup)    F2 = 80 col color",13,10
 db "      F3 = 40 col mono                 F4 = 40 col color",13,10
 db "      F5 = med res mono graphics       F6 = medium res color graphics",13,10
 db "      F7 = high res graphics           F10 = clears the current display page"
 db 13,10
 db "5) Ctrl-F1 thru Ctrl-F10 send (Epson) control codes to the printer.",13,10
 db "      F1 = slashed-zero                F2 = power-on reset",13,10
 db "      F3 = 10 cpi (80 col)             F4 = 17 cpi (132 col)",13,10
 db "      F5 = emphasized on               F6 = emphasized off",13,10
 db "      F7 = superscript mode            F8 = subscript mode",13,10
 db "      F9 = unidirectional              F10 = bidirectional",13,10
 db "6) The keypad '5' key is a toggle pause key.  While on, the letter P is"
    db    13,10
 db "   displayed, flashing and highlighted, in the lower right corner.",13,10
 db "7) Alt-PrtSc will toggle the enhanced keyboard on/off.  A beep signals on."
 db 13,10,10,"$"

not_yet db 9,"To make NEWINIT resident, type:  newinit install",13,10,10,"$"

cseg ends
    end    begin

move alt-fn and ctrl-fn to int-9