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Давайте создадим компилятор! :: Креншоу Джек
Страница: 205 из 382ess;
begin
EmitLn('SGT D0');
EmitLn('EXT D0');
end;
{–}
{ Set D0 If Compare was <= }
procedure SetLessOrEqual;
begin
EmitLn('SGE D0');
EmitLn('EXT D0');
end;
{–}
{ Set D0 If Compare was >= }
procedure SetGreaterOrEqual;
begin
EmitLn('SLE D0');
EmitLn('EXT D0');
end;
{–}
{ Store Primary to Variable }
procedure Store(Name: string);
begin
if not InTable(Name) then Undefined(Name);
EmitLn('LEA ' + Name + '(PC),A0');
EmitLn('MOVE D0,(A0)')
end;
{–}
{ Branch Unconditional }
procedure Branch(L: string);
begin
EmitLn('BRA ' + L);
end;
{–}
{ Branch False }
procedure BranchFalse(L: string);
begin
EmitLn('TST D0');
EmitLn('BEQ ' + L);
end;
{–}
{ Read Variable to Primary Register }
procedure ReadVar;
begin
EmitLn('BSR READ');
Store(Value[1]);
end;
{ Write Variable from Primary Register }
procedure WriteVar;
begin
EmitLn('BSR WRITE');
end;
{–}
{ Write Header Info }
procedure Header;
begin
WriteLn('WARMST', TAB, 'EQU $A01E');
end;
{–}
{ Write the Prolog }
procedure Prolog;
begin
PostLabel('MAIN');
end;
{–}
{ Write the Epilog }
procedure Epilog;
begin
EmitLn('DC WARMST');
EmitLn('END MAIN');
end;
{–}
{ Parse and Translate a Math Factor }
procedure BoolExpression; Forward;
procedure Factor;
begin
if Look = '(' then begin
Match('(');
BoolExpression;
Match(')');
end
else if IsAlpha(Look) then begin
GetName;
LoadVar(Value);
end
else
LoadConst(GetNum);
end;
{–}
{ Parse and Translate a Negative Factor }
procedure NegFactor;
begin
Match('-');
if IsDigit(Look) then
LoadConst(-GetNum)
else begin
Factor;
Negate;
end;
end;
{–}
{ Parse and Translate a Leading Factor }
procedure FirstFactor;
begin
case Look of
'+': begin
Match('+');
Factor;
end;
'-': NegFactor;
else Factor;
end;
end;
{–}
{ Recognize and Translate a Multiply }
procedure Multiply;
begin
Match('*');
Factor;
PopMul;
end;
{–}
{ Recognize and Translate a Divide }
procedure Divide;
begin
Match('/');
Factor;
PopDiv;
end;
{–}
{ Common Code Used by Term and FirstTerm }
procedure Term1;
begin
while IsMulop(Look) do begin
Push;
case Look of
'*': Multiply;
'/': Divide;
end;
end;
end;
{–}
{ Parse and Translate a Math Term }
procedure Term;
begin
Factor;
Term1;
end;
{–}
{ Parse and Translate a Leading Term }
procedure FirstTerm;
begin
FirstFactor;
Term1;
end;
{–}
{ Recognize and Translate an Add }
procedure Add;
begin
Match('+');
Term;
PopAdd;
end;
{–}
{ Recognize and Translate a Subtract }
procedure Subtract;
begin
Match('-');
Term;
PopSub;
end;
{–}
{ Parse and Translate an Expression }
procedure Expression;
begin
FirstTerm;
while IsAddop(Look) do begin
Push;
case Look of
'+': Add;
'-': Subtract;
end;
end;
end;
{–}
{ Recognize and Translate a Relational «Equals» }
procedure Equal;
begin
EmitLn('SGT D0');
EmitLn('EXT D0');
end;
{–}
{ Set D0 If Compare was <= }
procedure SetLessOrEqual;
begin
EmitLn('SGE D0');
EmitLn('EXT D0');
end;
{–}
{ Set D0 If Compare was >= }
procedure SetGreaterOrEqual;
begin
EmitLn('SLE D0');
EmitLn('EXT D0');
end;
{–}
{ Store Primary to Variable }
procedure Store(Name: string);
begin
if not InTable(Name) then Undefined(Name);
EmitLn('LEA ' + Name + '(PC),A0');
EmitLn('MOVE D0,(A0)')
end;
{–}
{ Branch Unconditional }
procedure Branch(L: string);
begin
EmitLn('BRA ' + L);
end;
{–}
{ Branch False }
procedure BranchFalse(L: string);
begin
EmitLn('TST D0');
EmitLn('BEQ ' + L);
end;
{–}
{ Read Variable to Primary Register }
procedure ReadVar;
begin
EmitLn('BSR READ');
Store(Value[1]);
end;
{ Write Variable from Primary Register }
procedure WriteVar;
begin
EmitLn('BSR WRITE');
end;
{–}
{ Write Header Info }
procedure Header;
begin
WriteLn('WARMST', TAB, 'EQU $A01E');
end;
{–}
{ Write the Prolog }
procedure Prolog;
begin
PostLabel('MAIN');
end;
{–}
{ Write the Epilog }
procedure Epilog;
begin
EmitLn('DC WARMST');
EmitLn('END MAIN');
end;
{–}
{ Parse and Translate a Math Factor }
procedure BoolExpression; Forward;
procedure Factor;
begin
if Look = '(' then begin
Match('(');
BoolExpression;
Match(')');
end
else if IsAlpha(Look) then begin
GetName;
LoadVar(Value);
end
else
LoadConst(GetNum);
end;
{–}
{ Parse and Translate a Negative Factor }
procedure NegFactor;
begin
Match('-');
if IsDigit(Look) then
LoadConst(-GetNum)
else begin
Factor;
Negate;
end;
end;
{–}
{ Parse and Translate a Leading Factor }
procedure FirstFactor;
begin
case Look of
'+': begin
Match('+');
Factor;
end;
'-': NegFactor;
else Factor;
end;
end;
{–}
{ Recognize and Translate a Multiply }
procedure Multiply;
begin
Match('*');
Factor;
PopMul;
end;
{–}
{ Recognize and Translate a Divide }
procedure Divide;
begin
Match('/');
Factor;
PopDiv;
end;
{–}
{ Common Code Used by Term and FirstTerm }
procedure Term1;
begin
while IsMulop(Look) do begin
Push;
case Look of
'*': Multiply;
'/': Divide;
end;
end;
end;
{–}
{ Parse and Translate a Math Term }
procedure Term;
begin
Factor;
Term1;
end;
{–}
{ Parse and Translate a Leading Term }
procedure FirstTerm;
begin
FirstFactor;
Term1;
end;
{–}
{ Recognize and Translate an Add }
procedure Add;
begin
Match('+');
Term;
PopAdd;
end;
{–}
{ Recognize and Translate a Subtract }
procedure Subtract;
begin
Match('-');
Term;
PopSub;
end;
{–}
{ Parse and Translate an Expression }
procedure Expression;
begin
FirstTerm;
while IsAddop(Look) do begin
Push;
case Look of
'+': Add;
'-': Subtract;
end;
end;
end;
{–}
{ Recognize and Translate a Relational «Equals» }
procedure Equal;
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