[fpc-pascal] EControlC instead of EZeroDivide when using SSE instructions

[OBones]

Olivier SANNIER wrote:
> Does any of you have any suggestion as to explain this behavior, and best of
> all, how to fix it?
I went further and changed the code this so that I can get better 
details as to where the exception is coming from:

program test;

uses
   sysutils,
   classes;

function GetMXCSR: Cardinal;
asm
   stmxcsr Result
end;

var
   PreviousExceptProc: TExceptProc;
   PreviousErrorProc: TErrorProc;

procedure MyExceptProc(Obj: TObject; Addr: Pointer; FrameCount: LongInt; 
Frame: PPointer);
begin
   WriteLn('MyExceptProc: ' + IntToHex(GetMXCSR, 2));
   WriteLn(Obj.ClassName);
   PreviousExceptProc(Obj, Addr, FrameCount, Frame);
end;

Procedure MyErrorProc(ErrNo : Longint; Address,Frame : Pointer);
begin
   WriteLn('MyErrorProc: ' + IntToHex(GetMXCSR, 2));
   WriteLn(ErrNo);
   PreviousErrorProc(ErrNo, Address, Frame);
end;

procedure MyTestExcept;
var
   Tmp: Double;
begin
   Tmp := 0.0;
   Tmp := 5.0 / Tmp;
end;

begin
   PreviousExceptProc := ExceptProc;
   ExceptProc := MyExceptProc;
   PreviousErrorProc := ErrorProc;
   ErrorProc := MyErrorProc;

   MyTestExcept;
end.

I compiled it in both x86 and x64 and then ran it. Here are the results:

============================== x86 ========================================
MyErrorProc: 1900
217
MyExceptProc: 1900
EControlC
An unhandled exception occurred at $004017CE :
EControlC : Control-C hit
   $004017CE  MYTESTEXCEPT,  line 64 of test.dpr
   $00401815  main,  line 76 of test.dpr

============================== x64 ========================================
MyErrorProc: 1900
200
MyExceptProc: 1900
EDivByZero
An unhandled exception occurred at $000000000040189B :
EDivByZero : Division by zero
   $000000000040189B  MYTESTEXCEPT,  line 64 of test.dpr
   $00000000004018FA  main,  line 76 of test.dpr

So clearly, there is an issue in the x86 build because the ErrorProc has 
the wrong runtime error code. Strangely enough, the MXCSR has none of 
its exception flags set, so it seems they are reset before ErrorProc is 
called

I would very much appreciate any help in solving this issue.

Regards
Olivier