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CD ROM Paradise Collection 4
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CD ROM Paradise Collection 4 1995 Nov.iso
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0056_PROTECTED MODE.pas
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Pascal/Delphi Source File
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1994-08-24
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3KB
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121 lines
{
SM> I have a bit of a problem with pascal 7 protected mode,
SM> I have a TSR (assembly) that does my comms work for me.
SM> I use intr(regs) with various settings to the registers to collect
SM> data from the TSR. However when in protected mode my TSR seems
SM> to be unavailable.
I had the same problem, it seems that the DOS unit does not support protected
mode interrupt handling. I solved it by looking though some documentation I
found on protected mode, below is a simple unit to set and get protected
mode interrupts.
In my case the interrupt goes about 22Khz so it kept switching into real mode
and back just to handle the interrupt, the result it crashed.
SM> Do I need to switch to real mode from the app.
SM> (if so how, I can't find it in the manual).
No, see above.
SM> Do I need to modify my TSR.
SM> I presume not because I'm sure that the mouse drivers can be got
SM> to work.
The MOUSE is handled by the DOS extender.
Cheers
Rob
P.S. I noticed that you use the same BBS, if you have any problems drop
me a note.
}
Unit DPMIDos; { This code was a quick hack job to solve my problem }
{ don't expect it to be neat! }
INTERFACE
Function RealMode : Boolean;
Function AllocateLDT(NumberDescriptors : Word) : Word;
Function FreeLDT(Selector : Word) : Boolean;
Function SegmentToDescriptor(Segment : Word) : Word;
Function GetNextSelectorInc : Word;
Function GetDPMIntVec(IntNumber : Byte) : Pointer;
Procedure SetDPMIntVec(IntNumber : Byte; IntVec : Pointer);
IMPLEMENTATION
Function RealMode : Boolean; assembler;
asm
mov ax, 01686h
int 02Fh
end;
Function AllocateLDT(NumberDescriptors : Word) : Word; assembler;
asm
mov ax, 0000h
mov ax, NumberDescriptors
int 031h
jnc @Ok
mov ax, 0
@Ok:
end;
Function FreeLDT(Selector : Word) : Boolean; assembler;
asm
mov ax, 0001h
mov bx, Selector
int 031h
mov ax, 1
jnc @Ok
mov ax, 0
@Ok:
end;
Function SegmentToDescriptor(Segment : Word) : Word; assembler;
asm
mov ax, 0002h
mov bx, Segment
int 31h
jnc @Ok
mov ax, 0
@Ok:
end;
Function GetNextSelectorInc : Word; assembler;
asm
mov ax, 0003h
int 031h
end;
Function GetDPMIntVec(IntNumber : Byte) : Pointer; {assembler;}
Var S, O : Word; { Too lazy to look in the manual! }
Begin
asm
mov ax, 0204h
mov bl, IntNumber
int 031h
mov S, cx
mov O, dx
end;
GetDPMIntVec := Ptr(S, O);
End;
Procedure SetDPMIntVec(IntNumber : Byte; IntVec : Pointer); assembler;
asm
mov ax, 0205h
mov bl, IntNumber
les dx, IntVec
mov cx, es
int 031h
end;
begin
end.