And my run of bugs continues: https://quality.embarcadero.com/browse/RSP-20351

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And my run of bugs continues: https://quality.embarcadero.com/browse/RSP-20351

This program:

{$APPTYPE CONSOLE}
var
D: Double;
U64: UInt64;
begin
D := high(UInt64);
Writeln(D);

U64 := high(UInt64);
D := U64;
Writeln(D);

Readln;
end.

should output

1.84467440737096E+0019
1.84467440737096E+0019

but in fact outputs

-1.00000000000000E+0000
1.84467440737096E+0019

I guess the compiler generates code as if the constant value was treated as a signed Int64.

Shout out to Stefan Glienke for bringing this one to my attention.

I have one more bug that I have seen, but not yet submitted.

Quite amazing what can be found with a little bit of effort. Imagine if the Emba team put in some serious testing effort?
https://quality.embarcadero.com/browse/RSP-20351

Comments

  1. Rafael DipoldApril 14, 2018 at 1:48 PM

    Sorry.. As both, Double and Int64, are 8 bits, so I deduced that the truncated value of whatever Double will within the Int64 range..

    ReplyDelete
  2. Leif UneusApril 14, 2018 at 2:24 PM

    Rafael Dipold The maximum double value is about 2E+289 times larger than the maximum Int64 value even though they both occupy 8 bytes.

    ReplyDelete
  3. David HeffernanApril 15, 2018 at 12:06 AM

    And in the other direction, when assigning an Int64 to double, double only has 53 bit mantissa so for large values you lose precision.

    ReplyDelete

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