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Programming => General => Topic started by: denis.totoliciu on July 08, 2020, 10:53:09 pm

Title: __llmod() equivalent
Post by: denis.totoliciu on July 08, 2020, 10:53:09 pm

Hello,

There is a routine declared as procedure __llmod() in the System unit in Delphi. The comment above it says: { 64-bit Integer helper routines }.
Looked for an equivalent with the same name in FPC, but couldn't find it. Maybe there is one, but with a different name.

The interest in this particular procedure comes from the attempt to compile the JCL package with FPC 32-bit. It resulted with an error that it can't find __llmod.

Do you know of such an equivalent routine?

Thank you!

Title: Re: __llmod() equivalent
Post by: jamie on July 08, 2020, 11:01:49 pm

its most likely a MOD operator which Fpc supports naturally ..

Please show a couple of lines of its use so others can determine what it is.

Title: Re: __llmod() equivalent
Post by: denis.totoliciu on July 08, 2020, 11:07:40 pm

Here is a sequence from zlibh.pas:

Code: Pascal  [Select][+][-]

1. {$IFDEF CPU32}
2. procedure __llmod; cdecl;
3. asm
4.   jmp System.@_llmod;
5. end;
6. {$ENDIF CPU32}
7.  
8. {$ENDIF ZLIB_STATICLINK}
9. {$ENDIF ~ZLIB_RTL}
10.  

It is not used in other parts of JCL.

Title: Re: __llmod() equivalent
Post by: marcov on July 08, 2020, 11:07:54 pm

Procedures starting with __ are internal, undocumented ones. They are not guaranteed to stay the same between Delphi versions either.

Maybe JCL used it because they use a lot of assembler, and such functions are easier to call in assembler, so the easiest solution is to let JCL take the pascal instead of the assembler code.

Title: Re: __llmod() equivalent
Post by: PascalDragon on July 09, 2020, 09:39:33 am

Quote from: denis.totoliciu on July 08, 2020, 11:07:40 pm

Here is a sequence from zlibh.pas:

Code: Pascal  [Select][+][-]

1. {$IFDEF CPU32}
2. procedure __llmod; cdecl;
3. asm
4.   jmp System.@_llmod;
5. end;
6. {$ENDIF CPU32}
7.  
8. {$ENDIF ZLIB_STATICLINK}
9. {$ENDIF ~ZLIB_RTL}
10.  

It is not used in other parts of JCL.

I think replacing it with the following should work (not tested):

Code: Pascal  [Select][+][-]

1. {$IFDEF CPU32}
2. {$IFNDEF FPC}
3. procedure __llmod; cdecl;
4. asm
5.   jmp System.@_llmod;
6. end;
7. {$ELSE FPC}
8. function __llmod(n,z: Int64): Int64; cdecl;
9. begin
10.   Result := n mod z;
11. end;
12. {$ENDIF FPC}
13. {$ENDIF CPU32}
14.  

Title: Re: __llmod() equivalent
Post by: marcov on July 09, 2020, 10:30:07 am

Of course this will move the problem only to the next bit, linking Delphi's zlib objs

Title: Re: __llmod() equivalent
Post by: PascalDragon on July 09, 2020, 11:30:00 am

The object files are part of JCL and are simple COFF object files. The other missing functions are fullfilled by imports from MSVCRT.