Unable to Cast UInt64 to Double on 32bit Compile in Windows 11 ARM: Has Anyone Experienced This?

[gomsun2 0]

I'm currently working on a MacBook Pro equipped with an M2 chip and using Parallels for virtualization to run Windows 11 ARM. I've encountered a peculiar issue. When I compile for 32bit, I'm not getting the result I anticipate. The code should produce an output of '3.0', but it consistently returns '0'.

Here's a snippet of the code causing the problem:

procedure TMainView.Button3Click(Sender: TObject);
begin
  var LValue: UInt64 := 3;
  Caption := LValue.ToDouble.ToString;
end;

I've found this to be consistent across several Delphi versions, specifically D10, D11, and D12. Has anyone else experienced this issue, or can offer any insight?

[Lajos Juhász 239]

You should try to debug the code. On an Intel Windows laptop I get the correct result '3'.

[David Heffernan 2300]

I've seen other reports similar to this. It smells like an emulator bug. 

[gomsun2 0]

25 minutes ago, Lajos Juhász said:

You should try to debug the code. On an Intel Windows laptop I get the correct result '3'.

When I switch to debugging mode, the evaluation result is still the same. It represents 0.
I don't have an Intel Mac for testing. However, when I asked my coworker to check on theirs, the issue was not replicated.

It seems this might be specific to Mac with the M-series processor running Winodws 11 ARM.

Edited October 31, 2023 by gomsun2

[gomsun2 0]

20 minutes ago, David Heffernan said:

I've seen other reports similar to this. It smells like an emulator bug. 

I agree, I reported it to the quality portal: https://quality.embarcadero.com/browse/RSB-7079

[Lajos Juhász 239]

59 minutes ago, gomsun2 said:

I agree, I reported it to the quality portal: https://quality.embarcadero.com/browse/RSB-7079

 

In my opinion this is the wrong place to report the error. Delphi compiles the code correctly, your environment is giving the wrong result eg. it's not a compiler bug.

[Arnaud Bouchez 380]

Perhaps the FPU/x87 is not well supported within the emulator.

IIRC the 32-bit Delphi RTL uses the FPU to make double-to-string conversion, using BCD conversions
https://www.felixcloutier.com/x86/fbstp

[David Heffernan 2300]

Well I'd not want to use rtl code to convert float to string anyway because it doesn't get it right for all floats

[eivindbakkestuen 43]

Compiling for 64 bit works, I presume?