source: branches/bigint/Instructions.pas

unit Instructions;

interface

uses
  Classes, SysUtils, Generics.Collections, Cpu;

type
  TParamType = (ptNone, ptNumber, ptIndirect, ptIndirect2);
  TParamTypeArray = array of TParamType;

  TInstructionInfo = class
    Instruction: TInstruction;
    Name: string;
    Params: TParamTypeArray;
    Description: string;
  end;

  TInstructionInfos = TObjectList<TInstructionInfo>;

  { TInstructionSet }

  TInstructionSet = class
    Items: TInstructionInfos;
    function SearchName(Name: string): TInstructionInfo;
    function SearchInstruction(Instruction: TInstruction): TInstructionInfo;
    function AddNew(Instruction: TInstruction; Name: string;
      Params: TParamTypeArray; Description: string): TInstructionInfo;
    constructor Create;
    destructor Destroy; override;
  end;


implementation

{ TInstructionSet }

function TInstructionSet.SearchName(Name: string): TInstructionInfo;
var
  I: Integer;
begin
  I := 0;
  while (I < Items.Count) and (Items[I].Name <> Name) do Inc(I);
  if I < Items.Count then Result := Items[I]
    else Result := nil;
end;

function TInstructionSet.SearchInstruction(Instruction: TInstruction
  ): TInstructionInfo;
var
  I: Integer;
begin
  I := 0;
  while (I < Items.Count) and (Items[I].Instruction <> Instruction) do Inc(I);
  if I < Items.Count then Result := Items[I]
    else Result := nil;
end;

function TInstructionSet.AddNew(Instruction: TInstruction; Name: string;
  Params: TParamTypeArray; Description: string): TInstructionInfo;
begin
  Result := TInstructionInfo.Create;
  Result.Instruction := Instruction;
  Result.Name := Name;
  Result.Params := Params;
  Result.Description := Description;
  Items.Add(Result);
end;

constructor TInstructionSet.Create;
begin
  Items := TInstructionInfos.Create;
  AddNew(inNop, 'NOP', [], 'No operation - The instruction doesn''t do anything.');
  AddNew(inHalt, 'HALT', [], 'It terminates program execution and halts processor. Processor can be waked up by interrupt.');
  AddNew(inLoadConst, 'LDC', [ptIndirect, ptNumber], 'Loads constant into address location.');
  AddNew(inLoadIndex, 'LDI', [ptIndirect, ptIndirect, ptNumber], 'Loads value from one memory location with added relative index to another.');
  AddNew(inLoad, 'LD', [ptIndirect, ptIndirect], 'Loads value from one memory location to another.');
  AddNew(inLoadMem, 'LDM', [ptIndirect, ptIndirect2], 'Loads value from one indirect memory location to another.');
  AddNew(inStoreMem, 'STM', [ptIndirect2, ptIndirect], 'Stotes value to indirect memory location from source location.');
  AddNew(inInc, 'INC', [ptIndirect], 'Increments value in specified register.');
  AddNew(inDec, 'DEC', [ptIndirect], 'Decrements value in specified register.');
  AddNew(inInput, 'IN', [ptIndirect, ptIndirect], 'Reads value from input port to register.');
  AddNew(inOutput, 'OUT', [ptIndirect, ptIndirect], 'Writes value from register to output port.');
  AddNew(inJump, 'JP', [ptNumber], 'Unconditional absolute jump to defined address.');
  AddNew(inJumpZero, 'JPZ', [ptIndirect, ptNumber], 'Jumps to given address if value of register is zero');
  AddNew(inJumpNotZero, 'JPNZ', [ptIndirect, ptNumber], 'Jumps to given address if value of register is not zero');
  AddNew(inPush, 'PUSH', [ptIndirect], 'Push memory location onto stack.');
  AddNew(inPop, 'POP', [ptIndirect], 'Pop item from stack and store it into memory location.');
  AddNew(inCall, 'CALL', [ptNumber], 'Call subroutine.');
  AddNew(inRet, 'RET', [], 'Return from subrotine.');
end;

destructor TInstructionSet.Destroy;
begin
  FreeAndNil(Items);
  inherited;
end;

end.