lkml.org 
[lkml]   [2002]   [Mar]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[PATCH] gcc-3.1 ffs problem, kernel 2.4.18
    Following patch is needed to compile linux-2.4.18 with xfs patch with
    recent gcc 3.1 snapshot. It is clearly bug in linux includes (they use
    asm code unconditionally, even on constants, and they can get constants
    if exposed to tree-inliner). Other asm includes might need fixing too,
    I saw asm-cris is fixed already.

    Beside this linux-2.4.18 compiled with gcc-3.1 20020311 works fine for
    me.

    diff -ur linux-/include/asm-i386/bitops.h linux/include/asm-i386/bitops.h
    --- linux-/include/asm-i386/bitops.h Thu Nov 22 20:46:18 2001
    +++ linux/include/asm-i386/bitops.h Tue Mar 5 21:08:15 2002
    @@ -316,6 +316,8 @@
    return (offset + set + res);
    }

    +#include <linux/bitops.h>
    +
    /**
    * ffz - find first zero in word.
    * @word: The word to search
    @@ -324,10 +326,16 @@
    */
    static __inline__ unsigned long ffz(unsigned long word)
    {
    - __asm__("bsfl %1,%0"
    - :"=r" (word)
    - :"r" (~word));
    - return word;
    + /* The generic_ffs function is used to avoid the asm when the
    + argument is a constant. */
    + if (__builtin_constant_p (word)) {
    + return (~word ? (unsigned long) generic_ffs ((int) ~word) - 1 : 32);
    + } else {
    + __asm__("bsfl %1,%0"
    + :"=r" (word)
    + :"r" (~word));
    + return word;
    + }
    }

    #ifdef __KERNEL__
    @@ -342,13 +350,19 @@
    */
    static __inline__ int ffs(int x)
    {
    - int r;
    -
    - __asm__("bsfl %1,%0\n\t"
    - "jnz 1f\n\t"
    - "movl $-1,%0\n"
    - "1:" : "=r" (r) : "g" (x));
    - return r+1;
    + /* The generic_ffs function is used to avoid the asm when the
    + argument is a constant. */
    + if (__builtin_constant_p (x)) {
    + return generic_ffs (x);
    + } else {
    + int r;
    +
    + __asm__("bsfl %1,%0\n\t"
    + "jnz 1f\n\t"
    + "movl $-1,%0\n"
    + "1:" : "=r" (r) : "g" (x));
    + return r+1;
    + }
    }

    /**
    --
    : Michal Moskal :::::::: malekith/at/pld.org.pl : GCS {C,UL}++++$ a? !tv
    : PLD Linux ::::::: Wroclaw University, CS Dept : {E-,w}-- {b++,e}>+++ h

    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-03-22 13:25    [W:0.026 / U:30.364 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site