Re: [Linux-NTFS-Dev] SOLVED - Re: PROBLEM: compiling NTFS write support

[Yuri P. <yu...@ac...>]

This is in fact bug in x86-64 ffs() implementation:

static __inline__ int ffs(int x)
{
	int r;

	__asm__("bsfl %1,%0\n\t"
		"cmovzl %2,%0" 
		: "=r" (r) : "g" (x), "r" (-1));
	return r+1;
}

"g" should be replaced with "rm".


Yuri

Anton Altaparmakov wrote:

>On Wed, 2004-05-12 at 12:56, and...@in... wrote:
>  
>
>>>On Wed, 2004-05-12 at 11:14, and...@in... wrote:
>>>      
>>>
>>>>Hi, I have found a problem compiling te source of kernel 2.6.6, if I
>>>>enable NTFS write support when i run "make" i get this error:
>>>>
>>>>....
>>>>  CC      fs/ntfs/inode.o
>>>>  CC      fs/ntfs/logfile.o
>>>>{standard input}: Assembler messages:
>>>>{standard input}:683: Error: suffix or operands invalid for `bsf'
>>>>make[2]: *** [fs/ntfs/logfile.o] Error 1
>>>>make[1]: *** [fs/ntfs] Error 2
>>>>make: *** [fs] Error 2
>>>>
>>>>my kernel version is:
>>>>Linux version 2.6.5-AS1500 (root@ntb-gozzolox) (gcc version 3.3.2
>>>>20031022
>>>>(Red Hat Linux 3.3.2-1)) #3 Thu Apr 15 10:13:11 CEST 2004
>>>>        
>>>>
>>The binutils ver is:
>>binutils-2.14.90.0.6-4
>>    
>>
>
>This happens because gcc (wrongly!) optimizes a variable into a constant
>and then ffs() fails to assemble because the bsfl instruction is only
>allowed with memory operands and not constants.
>
>/me hates gcc...
>
>Please try the below fix.  It uses generic_ffs() which is ffs() the slow
>way so it should build fine.
>
>Thanks a lot for your help.
>
>Best regards,
>
>	Anton
>  
>