我知道我缺少非常重要且可能非常简单的东西,但我不知道是什么。
program Project2;
{$APPTYPE CONSOLE}
uses
SysUtils;
type
TSomeClass = class(TObject)
private
FCreateDateTime: string;
public
constructor Create;
procedure SayYeah;
end;
constructor TSomeClass.Create;
begin
FCreateDateTime := DateTimeToStr(Now);
end;
procedure TSomeClass.SayYeah;
begin
Writeln('yeah @ ' + FCreateDateTime);
end;
procedure Doit;
asm
CALL TSomeClass.Create; // <= Access Violation
CALL TSomeClass.SayYeah;
CALL TSomeClass.Free;
end;
begin
try
Doit;
except
on E: Exception do
Writeln(E.ClassName, ': ', E.Message);
end;
Readln;
end.
为您提供信息:我希望了解如何在低级别上实现它,而不是其他方法。
更新:
感谢Andreas Rejbrand,我已经找到了罪魁祸首:
更新2:
感谢Arnaud使用EBX而非PUSH/POP EAX发现了缺陷
var
TSomeClass_TypeInfo: Pointer;
procedure Doit;
asm
MOV DL, $01;
MOV EAX, TSomeClass_TypeInfo;
CALL TSomeClass.Create;
PUSH EAX;
CALL TSomeClass.SayYeah; // call method
POP EAX;
MOV DL, $01;
CALL TSomeClass.Free; // pointer to instance(Self) is expected in EAX
end;
begin
TSomeClass_TypeInfo := TSomeClass;
try
Doit;
except
on E: Exception do
Writeln(E.ClassName, ': ', E.Message);
end;
Readln;
end.