Lazarus appear to wrong arithmetic operations with big nums.

[Tommi]

This simple code returns 148321786 and not 87956783576570.
I need it for crc64 operations.

Some idea ?

Thank You

procedure TForm1.Button2Click(Sender: TObject);
var
CRC64:TCRC64;
P:pointer;
a,b:integer;
x:int64;
begin
a:=8795678357657;b:=0;
edit1.Text:=inttostr(a*10);
end;

[cyber_python]

An integer can go up to 2,147,483,647 .
Use int64 instead of integer, which can go up to 9,223,372,036,854,775,807.
Hope this helps.

[Tommi]

I tried but it's the same.

In anycase Integer is also int64. (http://www.freepascal.org/docs-html/ref/refsu5.html#x25-240003.1.1)

Temporarily I solved so:


for cc := 1 to 256 do x:=x+a;     //the same as x:=a*256;

It works, but is very bad

[arnoldb]

It depends on the CPU target...

If you are compiling for I386 (default), integer is only 2 bytes and not the same as int64.

If you set your cpu target to Pentium Pro/ Pentium 2 in menu Project->Compiler Options->Code->Target i386, then FPC compiles for a 4-byte integer, which is the same as int64.

Hope this helps

[Marc]

in default mode (when no mode is specified) and interg is 16 bit (2 bytes)

In $mode objfpc (which all lazarus units are, see top of file) or in $mode delphi an integer is 32bit (4 bytes) indipendent of the CPU used

an int64 is allways 64 bit (8 bytes).

[Tommi]

Thank You, Issue is solved.