[fpc-pascal] How to translate Delphi Assembly MOV EAX,[EBP+4]

[Dennis]

Thanks.

So the following will give an address+frame of the calling routine ?
     get_caller_addr(get_frame),  get_caller_frame(get_frame)

Dennis

Sven Barth via fpc-pascal wrote:
> Dennis <dec12 at avidsoft.com.hk <mailto:dec12 at avidsoft.com.hk>> schrieb 
> am Mi., 18. Juli 2018, 17:19:
>
>     The following delphi code when compiled by FPC, raised these errors:
>     Compile Project, Target: lib\x86_64-win64\Project1.exe: Exit code 1,
>     Errors: 10, Warnings: 2
>     StrBuffer.pas(100,19) Error: Unknown identifier "EAX"
>     StrBuffer.pas(100,23) Error: Assembler syntax error in operand
>     StrBuffer.pas(100,24) Error: Unknown identifier "EBP"
>     StrBuffer.pas(100,29) Error: Invalid constant expression
>     StrBuffer.pas(100,29) Error: Invalid reference syntax
>     StrBuffer.pas(100,29) Warning: No size specified and unable to
>     determine
>     the size of the operands, using DWORD as default
>     StrBuffer.pas(207,19) Error: Unknown identifier "EAX"
>     StrBuffer.pas(207,23) Error: Assembler syntax error in operand
>     StrBuffer.pas(207,24) Error: Unknown identifier "EBP"
>     StrBuffer.pas(207,29) Error: Invalid constant expression
>     StrBuffer.pas(207,29) Error: Invalid reference syntax
>     StrBuffer.pas(207,29) Warning: No size specified and unable to
>     determine
>     the size of the operands, using DWORD as default
>
>     Can anyone help me?
>
>     class procedure TStrBuffer.Error(const Msg: string; Data: Integer);
>
>        function ReturnAddr: Pointer;
>        asm
>                MOV     EAX,[EBP+4]
>        end;
>
>     begin
>        raise EListError.CreateFmt(Msg, [Data])at ReturnAddr;
>     end;
>
>
> There are two ways to solve this.
>
> The first one is an easy one, however the code still won't be platform 
> independent due to the assembly code. For this simply add "{$asmmode 
> intel}" at the top.
>
> The second solution is cross platform and with correct checks also 
> Delphi compatible:
>
> === code begin ===
> raise EListError.CreateFmt(Msg, [Data]) at
> {$ifdef fpc}
> get_caller_addr(get_frame),
>     get_caller_frame(get_frame)
> {$else}
> ReturnAddr
> {$endif} ;
> === code end ===
>
> Disable the ReturnAddr function also with "{$ifndef fpc}...{$endif}" 
> and you should be set.
>
> Regards,
> Sven
>
>
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