Hi Joe,
> In Turbo Pascal's Turbo Vision, extended keyboards are detected once, upon
> program startup, like this:
>
> mov ax, 11ffh
> int 16h
> xor bl, bl
> cmp ax, 11ffh
> je @@1
> mov bl, 10h
> @@1:mov ReadKeyFunc, bl
>
> and then keyboard functions are called like this:
>
> mov ah, ReadKeyFunc
> (inc ah)
> int 16h
from which specific Turbo Pascal version is that code snippet? I did not find
this in the TV source shipped with Borland Pascal 7. Instead, I found this:
procedure GetKeyEvent(var Event: TEvent); assembler;
asm
MOV AH,1
INT 16H
MOV AX,0
MOV BX,AX
JE @@1
MOV AH,0
INT 16H
XCHG AX,BX
MOV AX,evKeyDown
@@1: XOR CX,CX
MOV DX,CX
CALL StoreEvent
end;
So no use of INT16.11 all. I may have overlooked it?
However, I did a few tests using DEBUG. The sequence
mov ax,11ffh
int 16h
seems to return some random value in AX (probably some previously entered key?)
under the specific BIOS I tested. However, I consider this value to be
undefined if the zero flag (no key in buffer) is set. So not sure if the
comparison
cmp ax,11ffh
is a reliable test. It would only be reliable if a) every BIOS supporting
INT16.11 does NOT return 11ffh, and every BIOS not supporting INT16.11 DOES
return 11ffh. I am not sure that this is the case. At least I nowhere found
this documented. Also, the source of the IBM-PC BIOSv3 [1] does speak against
it (AH=0 on return).
> Wouldn't the BIOS detect the extended keyboard when you call INT 16H, AH=11H?
> (Probably not but I though I'd ask. :-) ) Bye,
No, some only seem to detect when the first enhanced key is pressed.
[1]:
https://github.com/gawlas/IBM-PC-BIOS/blob/e6cae33370fa7cd0568d72b785f682971edcc70c/IBM%20PC/PCBIOSV3.ASM#L1839
Bernd
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