OpenEuphoria

Keyboard status function

• Posted by Marcel Kollenaar <M.Kollenaar at SLO.NL> May 01, 1997
• 963 views

To all Readers,

I needed a status indicator if the 'Insert' key was active. I couldn't
remember if our machine code Guru Jacques D. (positive) already coded
this and hadn't the time to ask for it. After short searching in
an old DOS programming book I found this.
I put it on the list maybe someone else might need it. The function
reads the status byte of the keyboard by int16h on location
0040:0017h. (or 0000:0417h)

Have a nice day,

Marcel Kollenaar

--Start code
include machine.e
constant    SHIFT_RIGHT = 1,
            SHIFT_LEFT  = 2,
            CONTROL     = 4,
            ALT         = 8,
            SCROLL_LOCK = 16,
            NUM_LOCK    = 32,
            CAPS_LOCK   = 64,
            INSERT      = 128

function kb_stat(atom mask)
-- Uses DOS INT #16, service #02 to read the status of the keyboard
-- Returns 1 if mask is in use else 0.
-- BIT  KEY                MASK
-- 0    right shift key    1
-- 1    left shift key     2
-- 2    Ctrl               4
-- 3    Alt                8
-- 4    Scroll lock        16
-- 5    Num lock           32
-- 6    Caps lock          64
-- 7    Insert             128

sequence reg_list

reg_list = repeat(0,10)
reg_list[REG_AX] = #0200
reg_list = dos_interrupt(#16,reg_list)
--
-- Because AH has still the function value #02, subtract AX with
-- #0200. After al not necessary!
--
return and_bits(reg_list[REG_AX]-#0200,mask) and mask
end function

if kb_stat(INSERT) then
    puts(1,"Insert key: ON\n")
else
    puts(1,"Insert key: OFF\n")
end if
if kb_stat(CAPS_LOCK) then
    puts(1,"Caps Lock key: ON\n")
else
    puts(1,"Caps Lock key: OFF\n")
end if
-- Code ends here