Programmer 7500/MAX_PROGRAMMERS.iso/INFO/C/CTASK22.ZIP/TSKKBD.ASM

Assembly Source File | 1990-10-12 | 14.0 KB | 727 lines

;
;    --- Version 2.2 90-10-12 14:51 ---
;
;    CTask - Keyboard handler module.
;
;    Public Domain Software written by
;        Thomas Wagner
;        Ferrari electronic Gmbh
;        Beusselstrasse 27
;        D-1000 Berlin 21
;        Germany
;
;    This module traps the keyboard interrupts to allow task switching
;    on waiting for a character.
;    To avoid problems with programs that access the keyboard buffer
;    directly instead of going through INT 16, the logic has been changed
;    in version 1.2. The keyboard characters are no longer placed into
;    a pipe, instead the keyboard hardware interrupt just sets a flag
;    to signal that there might be something in the buffer. The keyboard
;    read routines wait on this flag if the original INT 16 status call
;    indicates that no key is available.
;
;    Note that there is a slight chance of this logic leading to busy
;    waiting in the original INT 16. This could happen if the process
;    is interrupted between the status check and the actual keyboard
;    fetch, and the interrupting routine snatches away the keystroke.
;    Since this is not very likely to occur, and would not be fatal
;    anyway, it would be overkill to try to avoid this.
;
;    If INT 16 is entered via CTask's t_read_key and t_wait_key,
;    the stack is not switched.
;
;    In Version 2.1, the keyboard access routines (t_read_key etc.)
;    were moved to file 'tsksec.asm' to save code space in secondary
;    kernels. Also, the bug that the stack was always switched, contrary
;    to what the above paragraph said, was fixed.
;    The t_xxx routines now use the extended keyboard functions
;    if available. Function 5 (stuff keyboard buffer) is intercepted
;    to set the tsk_key_avail flag.
;
;    Version 2.1 adds hotkey processing to the INT 9 frontend.
;    It would be "nicer" to process hotkeys in the INT 15 scancode
;    intercept BIOS hook, but this hook is not present in older
;    XT and AT BIOSes. Version 2.2 will use the INT 15 entry if the
;    BIOS indicates that it does support it.
;
;    CAUTION: This module can only be installed in the primary kernel.
;         It is not ROMable.
;
    name    tskkbd
;
    include    tsk.mac
    include    tskdeb.h
;
    .tsk_model
;
    Pubfunc    tsk_install_kbd
    Pubfunc    tsk_remove_kbd
;
    public    tsk_key_avail
;
    Globext    create_flag
    Globext    delete_flag
    Globext    set_flag
    Globext    clear_flag
    Globext    wait_flag_set
    extrn    sched_int: far
    Locext    tsk_switch_stack
    Locext    tsk_old_stack
    Locext    tsk_timer_action
    Locext    tsk_dequeue
    Locext    tsk_putqueue
;
    IF    DEBUG AND DEB_FLASHERS
    Locext    tsk_inccdis
    extrn    tsk_debflash: word
    ENDIF
;
    extrn    tsk_glob_rec: byte
;
inta00        =    20h    ; 8259 int controller base
eoi        =    20h    ; unspecific EOI
;
keyb_data    =    60h    ; keyboard data port
keyb_ctl    =    61h    ; keyboard control (PC/XT only)
;
intseg    segment at 0
        org    09h*4
hwdoff        dw    ?    ; keyboard hardware interrupt
hwdseg        dw    ?
        org    15h*4
int15off     dw    ?    ; system services interrupt
int15seg     dw    ?
        org    16h*4
kbdoff        dw    ?    ; keyboard I/O interrupt
kbdseg        dw    ?
;
intseg    ends
;
biosdata    segment at 40h
        org    17h
keyb_flags_1    db    ?
keyb_flags_2    db    ?
        org    96h
keyb_flags_3    db    ?
;
biosdata    ends
;
;----------------------------------------------------------------------------
;
;    Variables
;
    .tsk_data
;
    IF    TSK_NAMEPAR
kbd_name    db    "KEYAVAIL",0
    ENDIF
;
tsk_key_avail    flag <>
;
    .tsk_edata
    .tsk_code
;
;
;    Original Interrupt-Entries
;
savhwd        label    dword        ; original hardware int entry
savhwdoff    dw    ?
savhwdseg    dw    ?
;
savkbd        label    dword        ; original keyboard I/O entry
savkbdoff    dw    ?
savkbdseg    dw    ?
;
savint15    label    dword        ; original system services entry
savint15off    dw    ?
savint15seg    dw    ?
;
ext_keyboard    db    0        ; extended keyboard BIOS present
kb_intercept    db    0        ; keyboard intercept is called
sched_pending    db    0        ; scheduler call is pending
;
;---------------------------------------------------------------------------
;
;    check_hotkey checks the hotkey queue passed in ES:BX for
;    a match. If there is a match, the associated action is
;    performed (via tsk_timer_action, since hotkey elements are
;    essentially timer elements).
;
;    Returns Carry set if no match, Carry clear on match.
;
    IF    HOTKEYS
;
@check_hotkey    proc    near
;
    push    ds
;
    mov    cx,SEG biosdata
    mov    ds,cx
    assume    ds:biosdata        ; for checking the flags
;
    cmp    es:telem.scancode[bx],0
    je    no_scancomp
;
checkhotloop:
    cmp    es:telem.scancode[bx],al
    jne    hot_next            ; no more checks on mismatch
;
no_scancomp:
    cmp    es:telem.kbflags1.hf_mask[bx],0        ; check flag 1?
    je    no_flcomp1                ; jump if not
;
    mov    ah,keyb_flags_1
    and    ah,es:telem.kbflags1.hf_mask[bx]
    cmp    ah,es:telem.kbflags1.hf_value[bx]
    jne    hot_next            ; no more checks on mismatch
;
no_flcomp1:
    cmp    es:telem.kbflags2.hf_mask[bx],0        ; check flag 2?
    je    no_flcomp2                       ; jump if not
;
    mov    ah,keyb_flags_2
    and    ah,es:telem.kbflags2.hf_mask[bx]
    cmp    ah,es:telem.kbflags2.hf_value[bx]
    jne    hot_next            ; no more checks on mismatch
;
no_flcomp2:
    cmp    es:telem.kbflags3.hf_mask[bx],0        ; check flag 3?
    je    do_hotkey                       ; match if not
;
    mov    ah,keyb_flags_3
    and    ah,es:telem.kbflags3.hf_mask[bx]
    cmp    ah,es:telem.kbflags3.hf_value[bx]
    je    do_hotkey            ; match
;
hot_next:
    les    bx,es:tlink.q_next[bx]        ; next in queue
    test    es:q_kind[bx],Q_HEAD        ; queue end?
    jnz    no_hotkey
    cmp    es:telem.scancode[bx],0
    je    no_scancomp
    jmp    checkhotloop
;
no_hotkey:
    sti
    pop    ds
    assume    ds:@CTASK_DATA
    stc
    ret
;
;    Execute hotkey action. First, remove from queue to allow
;    enable/disable/delete calls in the hotkey action.
;
do_hotkey:
    pop    ds
    cli
    or    es:tflags[bx],TFLAG_BUSY    ; mark busy
    push    si
    push    es
    push    bx
    callp    tsk_dequeue,<<es,bx>>        ; remove
    sti
    pop    bx
    pop    es
;
    push    es
    push    bx
    callp    tsk_timer_action,<<es,bx>>
    pop    bx
    pop    es
    pop    si
;
;    If continued hotkey, re-enqueue.
;
    cli
    test    es:tflags[bx],TFLAG_UNQUEUE OR TFLAG_REMOVE
    jnz    no_enque
    test    es:tflags[bx],TFLAG_ENQUEUE OR TFLAG_REPEAT
    jz    no_enque
    push    es
    push    bx
    callp    tsk_putqueue,<<ds,si>,<es,bx>>
    pop    bx
    pop    es
;
no_enque:
    and    es:tflags[bx],NOT (TFLAG_BUSY OR TFLAG_UNQUEUE OR TFLAG_ENQUEUE)
    sti
;     carry is now clear
    ret
;
@check_hotkey    endp
;
    ENDIF
;
;---------------------------------------------------------------------------
;
;    void tsk_install_kbd (void)
;
;        Install keyboard handler
;
Localfunc tsk_install_kbd
;
    IFDEF    LOAD_DS
    push    ds
    mov    ax,@CTASK_DATA
    mov    ds,ax
    ENDIF
;
;    Check for extended keyboard BIOS functions. Since there is no
;    error return when executing the functions in non-extended BIOS
;    versions, we have to do a little guesswork.
;
    mov    cs:ext_keyboard,0
;
    push    ds
    mov    ax,40h
    mov    ds,ax
    assume    ds:biosdata
;
    mov    ax,11ffh    ; this certainly is no valid key
    int    16h        ; get extended status
    cmp    ax,11ffh    ; has the value changed?
    je    not_extended    ; if not, it's surely not extended.
    cli
    mov    bl,keyb_flags_1
    mov    ah,12h
    int    16h
    cmp    bl,al
    jne    not_extended
    not    al
    mov    keyb_flags_1,al
    mov    ah,12h
    int    16h
    mov    keyb_flags_1,bl
    sti
    not    al
    cmp    bl,al
    jne    not_extended
;
;    An extended keyboard BIOS is present. This BIOS likely also supports
;    the INT 15 intercept hook, so check for it with the "return config
;    parameters" call.
;
    inc    cs:ext_keyboard
    IF    HOTKEYS
    mov    ah,0c0h
    int    15h
    jc    not_extended
    or    ah,ah
    jnz    not_extended
    cmp    word ptr es:[bx],8
    jb    not_extended
    test    byte ptr es:5[bx],10h    ; keyboard intercept present
    jz    not_extended
    inc    cs:kb_intercept
    ENDIF
;
not_extended:
    sti
    pop    ds
;
    assume    ds:@CTASK_DATA
;
    IF    TSK_NAMEPAR
    callp    create_flag,<<ds,#tsk_key_avail>,<ds,#kbd_name>>
    ELSE
    callp    create_flag,<<ds,#tsk_key_avail>>
    ENDIF
;
;    Save old interrupt vectors
;
        push    es
    xor    ax,ax
    mov    es,ax
;
        assume  es:intseg
;
    mov    ax,kbdoff
    mov    savkbdoff,ax
    mov    ax,kbdseg
    mov    savkbdseg,ax
;
    mov    ax,hwdoff
    mov    savhwdoff,ax
    mov    ax,hwdseg
    mov    savhwdseg,ax
;
    IF    HOTKEYS
    cmp    cs:kb_intercept,0
    je    enter_new
    mov    ax,int15off
    mov    savint15off,ax
    mov    ax,int15seg
    mov    savint15seg,ax
    cli
    mov    int15off,offset @intercept
    mov    int15seg,cs
    ENDIF
;
;    Enter new Interrupt-Entries
;
enter_new:
    cli
    mov    kbdoff,offset @kbdentry
    mov    kbdseg,cs
    mov    hwdoff,offset @hwdentry
    mov    hwdseg,cs
    sti
        pop     es
;
    IFDEF    LOAD_DS
    pop    ds
    ENDIF
    ret
;
    assume    es:nothing
;
tsk_install_kbd    endp
;
;
;    void tsk_remove_kbd (void)
;
;        Un-install keyboard handler
;
Localfunc tsk_remove_kbd
;
    IFDEF    LOAD_DS
    push    ds
    mov    ax,@CTASK_DATA
    mov    ds,ax
    ENDIF
;
        push    es
    xor    ax,ax
    mov    es,ax
;
        assume  es:intseg
;
;    Restore interrupt entries
;
    cli
;
    mov    ax,savkbdoff
    mov    kbdoff,ax
    mov    ax,savkbdseg
    mov    kbdseg,ax
;
    mov    ax,savhwdoff
    mov    hwdoff,ax
    mov    ax,savhwdseg
    mov    hwdseg,ax
;
    IF    HOTKEYS
    cmp    cs:kb_intercept,0
    je    rest_ready
    mov    ax,savint15off
    mov    int15off,ax
    mov    ax,savint15seg
    mov    int15seg,ax
    ENDIF
;
rest_ready:
    sti
;
        pop     es
;
;    Delete the keyboard available flag
;
    callp    delete_flag,<<ds,#tsk_key_avail>>
;
    IFDEF    LOAD_DS
    pop    ds
    ENDIF
    ret
;
    assume    es:nothing
;
tsk_remove_kbd    endp
;
;
;
;---------------------------------------------------------------------------
;---------------------------------------------------------------------------
;
;    INT 9 - Keyboard hardware interrupt
;
;    Version 2.1 adds hotkey processing.
;
@hwdentry    proc    far
;
        call    tsk_switch_stack
    IF    DEBUG AND DEB_FLASHERS
    cmp    tsk_debflash,0
    je    debdd0
    mov    ax,DEBP_CNTKEYBD
    call    tsk_inccdis
debdd0:
    ENDIF
;
;    Check the scancode hotkey queue.
;    Two queues are maintained for hotkeys, one for hotkey elements
;    with nonzero scancode, and one for zero scancode elements.
;    If there is no scancode, the hotkey is a shift-key combination,
;    which can only be checked *after* chaining to the old INT 9.
;    Hotkeys with scancode have to be checked *before* chaining,
;    so the scancode can be removed on a match.
;    If the BIOS supports keyboard intercept, this part is skipped.
;
    IF    HOTKEYS
    cmp    cs:kb_intercept,0
    jne    no_firstcheck
    lea    si,tsk_glob_rec.hotkey_scan.q_first
    les    bx,dword ptr [si]
    test    es:q_kind[bx],Q_HEAD    ; queue empty?
    jnz    no_firstcheck        ; then don't read key
    in    al,keyb_data
    call    @check_hotkey
    jnc    hotkey_found        ; remove scancode on match
;
no_firstcheck:
    ENDIF
;
    pushf
        cli
    call    cs:savhwd        ; let original handler process key
;
    callp    set_flag,<<ds,#tsk_key_avail>>
;
;    check no-scancode hotkeys
;
    IF    HOTKEYS
    lea    si,tsk_glob_rec.hotkey_noscan.q_first
    les    bx,dword ptr [si]
    test    es:q_kind[bx],Q_HEAD    ; queue empty?
    jnz    no_nshot        ; don't check if yes
    call    @check_hotkey
    jnc    immed_sched        ; schedule on hotkey match
;
no_nshot:
    cmp    cs:sched_pending,0
    jne    immed_sched
    ENDIF
;
    iret
;
    IF    HOTKEYS
hotkey_found:
;
;    Acknowledge keyboard, so hotkey disappears.
;
    cli
    in    al,keyb_ctl
    mov    ah,al
    or    al,80h
    out    keyb_ctl,al
    xchg    ah,al
    out    keyb_ctl,al
;
    mov    al,eoi
    out    inta00,al
    sti
;
;    on a hotkey match, we schedule immediately.
;
immed_sched:
    cli
    mov    cs:sched_pending,0
    mov    al,0bh            ; access int control reg
    out    inta00,al
    in    al,inta00        ; ints pending?
    or    al,al
    jnz    no_immed        ; don't schedule if other ints active
    sti
    call    tsk_old_stack
    jmp    sched_int
;
no_immed:
    iret
    ENDIF
;
@hwdentry    endp
;
;
    IF    HOTKEYS
;
@intercept    proc    far
;
    cmp    ah,4fh
    je    do_intercept
    jmp    cs:savint15
;
do_intercept:
    pushf
    sti
    cld
    push    ds
    push    es
    push    si
    push    di
    push    bx
    push    ax
    mov    si,@CTASK_DATA
    mov    ds,si
;
    lea    si,tsk_glob_rec.hotkey_scan.q_first
    les    bx,dword ptr [si]
    test    es:q_kind[bx],Q_HEAD    ; queue empty?
    jz    inter_check
    stc
    jmp    short inter_ret
;
inter_check:
    push    cx
    push    dx
    call    @check_hotkey
    pop    dx
    pop    cx
;
inter_ret:
    pop    ax
    pop    bx
    pop    di
    pop    si
    pop    es
    pop    ds
    jc    inter_chain
    popf
    mov    cs:sched_pending,1
    clc
    ret    2
;
inter_chain:
    popf
    jmp    cs:savint15
;
@intercept    endp
;
    ENDIF
;
;---------------------------------------------------------------------------
;---------------------------------------------------------------------------
;
;    INT 16 - Keyboard I/O
;
@kbdentry    proc    far
;
        pushf
    sti
    or    ah,ah
    jz    kbd_read
    cmp    ah,10h
    jz    kbd_read_ext    ; extended read
    cmp    ah,05h
    jz    kbd_stuff    ; stuff char in key buffer
    cmp    ax,4012h
    jz    kbd_readns
    cmp    ax,4112h
    jz    kbd_readns
    cmp    ax,4212h
    jz    kbd_keyhit
;
kbd_pass:
        popf
    jmp    cs:savkbd    ; pass on functions != 0
;
;    The "4212" code is used by t_keyhit. It will execute function
;    1 or 11h depending on ext_keyboard.
;
kbd_keyhit:
    mov    ah,1
    cmp    cs:ext_keyboard,0
    je    kbd_pass
    mov    ah,11h
    jmp    kbd_pass
;
;    The "4012" and "4112" codes are used by t_wait_key and t_read_key.
;    The t_wait_key code 4012 uses the timeout supplied in CX:DX.
;    The t_read_key code 4112 uses an endless timeout (0L).
;
kbd_readns:
    popf            ;2.1a
    sti            ;2.1a
    push    ds        ;2.1a
    mov    bx,@CTASK_DATA    ;2.1a
    mov    ds,bx        ;2.1a
    mov    bx,8001h
    cmp    cs:ext_keyboard,0
    je    readns1
    mov    bx,9011h
readns1:
;2.1a    popf
    cmp    ah,40h
    jne    kbd_read2
    jmp    short kbr_loop
;
kbd_stuff:
        popf
    call    cs:savkbd
    call    tsk_switch_stack
    mov    ax,entry_flags[bp]
    mov    caller_flags[bp],ax
    callp    set_flag,<<ds,#tsk_key_avail>>
    iret
;
kbd_read_ext:
    cmp    cs:ext_keyboard,0
    je    kbd_pass        ; pass on if no extended kbd
    mov    al,11h
    jmp    short kbd_read1
;
kbd_read:
    mov    al,1
kbd_read1:
        popf
    call    tsk_switch_stack
    mov    bx,ax
kbd_read2:
    xor    cx,cx
    mov    dx,cx
;
kbr_loop:
    push    bx
    push    cx
    push    dx
    callp    clear_flag,<<ds,#tsk_key_avail>>
    pop    dx
    pop    cx
    pop    bx
    mov    ah,bl
    pushf
    cli
    call    cs:savkbd
    jnz    kbr_get_key
    push    bx
    push    cx
    push    dx
    callp    wait_flag_set,<<ds,#tsk_key_avail>,<cx,dx>>
    pop    dx
    pop    cx
    pop    bx
    or    ax,ax
    jz    kbr_loop
    mov    ax,-1
    jmp    short kbr_retn
;
kbr_get_key:
    mov    ah,bh
    and    ah,7fh
    pushf
    cli
    call    cs:savkbd
kbr_retn:
    test    bh,80h
    jnz    kbr_retns
    mov    save_ax[bp],ax
    iret            ;2.1a
kbr_retns:
    pop    ds        ;2.1a
    iret
;
@kbdentry    endp
;
    .tsk_ecode
    end