fpc/rtl/amiga/m68k/m68kamiga.inc
2015-05-24 21:43:13 +00:00

67 lines
1.7 KiB
PHP

{
This file is part of the Free Pascal run time library.
Copyright (c) 2015 by Karoly Balogh,
member of the Free Pascal development team.
m68k/Amiga atomic operations implementation
See the file COPYING.FPC, included in this distribution,
for details about the copyright.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
**********************************************************************}
{ The Amiga hardware doesn't support the m68k CPU's atomic operations
like TAS, CAS, CAS2 and so on. Therefore we must "emulate" them from
software. The easiest way is the Forbid()/Permit() OS call pair around
the ops themselves. It of course won't be hardware-atomic, but should
be safe for multithreading. (KB) }
function InterLockedDecrement (var Target: longint) : longint;
begin
Forbid;
Dec(Target);
Result := Target;
Permit;
end;
function InterLockedIncrement (var Target: longint) : longint;
begin
Forbid;
Inc(Target);
Result := Target;
Permit;
end;
function InterLockedExchange (var Target: longint;Source : longint) : longint;
begin
Forbid;
Result := Target;
Target := Source;
Permit;
end;
function InterLockedExchangeAdd (var Target: longint;Source : longint) : longint;
begin
Forbid;
Result := Target;
Target := Target + Source;
Permit;
end;
function InterlockedCompareExchange(var Target: longint; NewValue: longint; Comperand: longint): longint;
begin
Forbid;
Result := Target;
if Target = Comperand then
Target := NewValue;
Permit;
end;