97 lines
2.1 KiB
ObjectPascal
97 lines
2.1 KiB
ObjectPascal
{ ************************************************
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* Asuro
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* Unit: Scheduler
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* Description: Schedules Context Switches
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************************************************
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* Author: Aaron Hance
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* Contributors:
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************************************************ }
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unit scheduler;
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interface
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uses
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console,
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isr32,
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lmemorymanager;
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const
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Quantum = 64;
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type
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TTaskState = packed record
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//EAX, EDX,
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end;
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TScheduler_Entry = packed record
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ThreadID : uint32;
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Priority : uint8;
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Delta : uint32;
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Next : void;
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end;
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PScheduler_Entry = ^TScheduler_Entry;
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var
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Active : Boolean;
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procedure init;
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procedure add_task(priority : uint8);
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implementation
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var
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Tick : uint32;
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Root_Task : PScheduler_Entry = nil;
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Current_Task : PScheduler_Entry = nil;
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procedure context_switch();
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begin
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Current_Task:= PScheduler_Entry(Current_Task^.Next);
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end;
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procedure add_task(priority : uint8);
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var
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new_task : PScheduler_Entry;
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task : PScheduler_Entry;
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i : uint32;
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begin
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new_task:= PScheduler_Entry(kalloc(sizeof(TScheduler_Entry)));
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new_task^.Priority:= priority;
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new_task^.Delta:= Tick;
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new_task^.Next:= void(Root_Task);
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task:= Root_Task;
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i:= 1;
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while PScheduler_Entry(task^.next) <> Root_Task do begin
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i:= i+1;
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task:= PScheduler_Entry(task^.next);
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end;
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task^.next:= void(new_task);
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new_task^.ThreadID:= i;
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end;
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procedure delta(data : void);
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begin
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If Active then begin
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Tick:= Tick + 1;
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If Tick = 0 then context_switch();
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If (Current_Task^.Delta + (Current_Task^.Priority * Quantum)) <= Tick then context_switch();
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end;
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end;
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procedure init;
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begin
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console.writestringln('SCHEDULER: INIT BEGIN.');
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Root_Task:= PScheduler_Entry(kalloc(sizeof(TScheduler_Entry)));
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Root_Task^.ThreadID:= 0;
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Root_Task^.Priority:= 1;
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Root_Task^.Delta:= 0;
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Root_Task^.Next:= void(Root_Task);
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Current_Task:= Root_Task;
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Tick:= 0;
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Active:= False;
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isr32.hook(uint32(@delta));
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console.writestringln('SCHEDULER: INIT END.');
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end;
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end. |